adobe
A mixture of silt and clay, dried in the sun, used to make reddish brown bricks for building. |
aerial sextant
A navigational instrument used to determine the location of an aircraft relative to the
earth’s surface. |
aeronautics
The study and practice of travel through the air. |
aft
At or near the stern (rear) of a ship. |
alloy
A metal made of a mixture of two or more other metals; bronze, for example, is an alloy of copper and tin. |
altitude
Height above the surface of the earth. |
amber
A fossil resin of yellow-orange color. |
amidships
Toward the part of a ship midway between the bow (at the front) and the stern (at the rear). |
anchorage
A place suitable for anchoring a ship. |
anthropology
The study of human beings, especially in relation to their society and culture. |
Aragon
With Castile, one of the two powerful Spanish kingdoms of the late Middle Ages (Aragon and Castile were united in 1479). |
Arikara
A member of an American Indian people that lived in circular dome-shaped earth lodges along the upper Missouri River. |
asteroid
A small celestial body, usually a piece of rock. |
asteroid
belt A region of space between the orbits of Mars and Jupiter where large numbers of asteroids are found. |
astrolabe
An instrument used to determine the position of the sun, moon, stars, and planets. |
atmosphere
The layer of gasses around a planet. |
atoll
An island consisting of a circular belt of coral with a central lagoon. |
aurora borealis
An atmospheric phenomenon that causes streaks of colored light to appear in the night sky above the northern polar region. |
Aztec
A member of a people who ruled a large empire in central and southern Mexico during the fifteenth century, before the arrival of the Spanish conquistadores. |
ballast
A heavy substance carried on board ships, balloons, and submersibles that improves the stability or controls the ascent and descent of a vessel. |
barometer
An instrument that measures changes in atmospheric pressure. |
barometric pressure
A measurement of the pressure of the earth’s atmosphere, which changes according to the weather. |
bathyscaphe
A diving vessel for deepsea observation that is lowered by a cable from a ship. |
bathysphere
A spherical deep-sea observation vessel. |
bearing
The relationship of one point to another on the earth’s surface.The bearing of point B from point A is the angle between the lines AB and AN, where N is any point due north of A. |
bends
Decompression sickness caused when nitrogen bubbles form in the body’s tissues. |
black hole
A hypothetical point in space of zero volume and infinite mass; the gravitational pull of a black hole is so strong that no object or light can escape from it. |
botany
The branch of biology dealing with plants. |
botulism
A serious form of food poisoning caused by eating preserved food that has been contaminated with botulinum organisms. |
bowsprit
A long wooden post that projects forward from the front of a ship. |
braggart
A loud and arrogant boaster. |
buccaneer
Name given to English, French, or Dutch sailors who attacked and raided Spanish and Portuguese ships and colonies in the New World. |
caliph
Title used in various Islamic empires for leaders who traced their descent to the prophet Muhammad. |
caravel
A small, fast Spanish or Portuguese ship with lateen (triangular) sails. |
cartography
The science and art of mapmaking. |
carvel-built
Referring to the hull of a ship constructed by fitting planks to a preconstructed frame and making the surface level by caulking the gaps. |
catamaran
A ship or boat that has two hulls and is therefore difficult to capsize. |
caulk
To stop and make watertight, for example, the gaps between the planks of a ship or cracks in a window frame. |
celestial
Of or relating to the skies, stars, and heavens. |
cholera
An infectious, often fatal, disease that causes severe vomiting. |
Cholulan
A member of an American Indian civilization that flourished around modern Puebla in central Mexico and was probably closely connected to the Aztecs. |
chronometer
A clock capable of keeping accurate time on board a ship. The name derives from two Greek
words: chronos (time) and metron (measure). |
clinker-built
Referring to the hull of a ship constructed of overlapping planks. |
coal-tar naphtha
A waste product of the tar-making process. |
cog
A clinker-built, square-rigged,wide transport ship of the Middle Ages, the first to include a rudder in place of a steering oar. |
collier
A small ship whose job was to transport coal. |
colony
A settlement or entire country governed by and owing allegiance to a mother country, which may be some distance away. |
Comanche
A member of a Native American people who lived by raiding and hunting buffalo on the southern Great Plains. |
Comanche
A member of a Native American people who lived by raiding and hunting buffalo on the southern Great Plains. |
comet
A celestial body that follows a highly eccentric orbit around the sun; many comets trail a tail of dust behind them when they near the sun. |
conquistador
The Spanish word for “conqueror”; specifically, any of the soldiers, explorers, or settlers who, in the wake of Columbus’s discovery of the Americas, helped to establish the Spanish presence in Central and South America during the sixteenth century. |
continental shelf
The area of the ocean floor closest to land. |
corona
The outermost part of a sun’s atmosphere. |
corvette
A small eighteenth-century warship, usually with one main deck and one tier of cannon. |
crane
A large long-legged bird. |
creditor
One who lends money or to whom money is owed. |
Cree
A member of a major group of Algonquian peoples that once inhabited a vast swath of Canada stretching from Hudson Bay west as far as the Great Slave Lake. |
Crusade
One of several Christian military expeditions, especially in the eleventh, twelfth, and thirteenth centuries, whose purpose was to regain the Holy Land from the Muslims. |
curragh
An open leather boat with no keel and made of animal skins stretched over a wooden frame; used by the Celts of Ireland and Scotland during the Middle Ages. |
delta
An often triangular area at the mouth of a river, where the sediment (rocks, gravel, and other material carried by the current) laid down has caused the river to split into channels. |
dhow
A light yet strong wooden ship, with triangular sails and a short mast, used by medieval Arab traders. |
dodo
A large flightless bird, like a turkey, that lived on the island of Mauritius but is now extinct. |
doldrums
Ocean region near the equator where calms, sudden storms, and light, unpredictable winds predominate. |
dowry
Property a woman brings to her husband when they marry. |
draft
The depth that the submerged part of a vessel lies beneath the water. |
ducado
A Spanish monetary unit, equivalent to 1.33 ounces (37.6 gm) of gold; also known as a ducat. |
dysentery
An infection that causes severe diarrhea. |
ebony
A dark, hard, heavy wood. |
electromagnetic radiation
Energy waves (including visible light, radio waves, and X rays) produced by periodic variations in the electric and magnetic fields of their source. Electromagnetic radiation is dominant on an atomic level but can extend over large distances. |
electromagnetic spectrum
The range of all known wave energy in the universe, including visible light, invisible light (such as infrared and ultraviolet), and radio waves. |
encomienda
The medieval Castilian landholding system, involving forced labor and tribute, especially as transferred to New Spain. |
Enlightenment
An intellectual movement of eighteenth-century Europe that rejected traditional social, political, and religious arrangements and ideas in favor of new ones more closely based on logic, reasoning, and scientific observation. |
entrepreneur
A person who, often at some risk, sets up a business. |
equinox
A twice-yearly event, usually occurring around March 22 and September 22,when the sun crosses the celestial equator and day and night are of equal length. |
evangelical
Christianity A form of Christianity whose adherents believe in the sole and literal authority of the Bible. |
expeditionary force
A group of explorers, usually army or navy officers. |
extraterrestrial
Referring to something whose origin is somewhere other than Earth. |
feudal
Referring to a system of political and social organization that prevailed in medieval Europe, according to which a commoner was obliged to serve a lord in return for protection and, usually, the right to farm land. |
fiber-optic cable
A cable containing many thin, flexible, transparent fibers, often used to carry telecommunications. |
fjord
A narrow inlet of the sea surrounded by high cliffs. |
folklore
The body of traditional tales, customs, and art forms preserved, often orally, among any given people. |
forage
Food for cattle and horses such as grasses and hay, usually found or carried by travelers. |
ford
A place where a river is shallow enough to be crossed. |
fore
At or near the front of a ship. |
foundry
A factory where metals, usually iron, are smelted and moulded into shape. |
Franciscan
A member of one of the Roman Catholic religious orders of men or women founded by Saint Francis of Assisi in 1209 or an offshoot of one of those orders. |
frequency
A mathematical property (the number of oscillations per second) that distinguishes one form of wave energy from another. |
frieze
An ornamental sculptured band on a building or piece of furniture. |
frostbite
A medical condition in which skin and underlying tissues freeze. If blood circulation is not restored to the affected area, frostbite degenerates into gangrene. |
gabardine
A smooth, hard-wearing twilled cloth. |
galleon
A large wooden sailing ship used for warfare and commerce, especially by the Spanish during the fifteenth and sixteenth centuries. |
gangrene
A condition, caused by loss of blood supply to an area of the body, that causes the flesh to rot. |
geology
The study of the origin and structure of the earth. |
geostationary
Referring to the orbit of a satellite whose altitude and velocity are such that the satellite remains over the same point of the earth’s surface as the earth spins. |
glacier
A large body of ice that moves slowly down a valley. As a glacier moves, it erodes rocks and soil. |
gonfalonier
In a medieval Italian republic, a chief magistrate. |
gradient
A slope, expressed as the rate of ascent or descent in relation to the distance covered. |
gravity
The fundamental physical force that one object exerts on another.The size of an object is the primary factor governing the gravitational force it exerts. |
greenhouse effect
The rise in temperature of the surface and lower atmosphere of the earth or another
planet caused by a high presence in the atmosphere of carbon dioxide, which traps reflected heat. |
grid
A network of parallel lines intersecting at right angles to produce a series of identical squares. |
hajj
The pilgrimage to Mecca that Islam requires all its adherents to make once in their lifetime. |
hemisphere
Half of a sphere; specifically, a half of the earth. |
heresy
A religious belief that runs counter to an official teaching of a church or, for that matter, to a dominant opinion in a society or state. |
hidalgo
A member of the lower Spanish nobility. |
hold
The interior area of a ship where cargo and the crew’s food stores are generally carried. |
hydrography
The study of seas, lakes, and rivers, especially the charting of tides or the measurement of river flow. |
hypothermia
Dangerously low body temperature caused by prolonged exposure to cold. |
Iberian Peninsula
The southwestern part of the European landmass that includes Spain and Portugal. |
iceberg
A floating mountain of ice; an iceberg is formed when a slab of ice breaks off a glacier (a frozen river) as it reaches the sea. |
Inca
A member of a people who ruled a large empire in northwestern South America from the thirteenth century until the sixteenth, when it fell to the Spanish conquistadores. |
Inca Road
The main north-south highway of the Incan Empire,which stretches some 4,350 miles (7,000 km) from Colombia to Chile at altitudes between 3,300 and 14,750 feet (1,000–4,500 m). |
incumbency
The period of time during which an official position, such as the presidency of a country, is held. |
Indian agent
A U.S. government official who served as a link with a particular Indian tribe. |
intendant
A senior official in New France who was in charge of economic affairs and represented the governor in his absence. |
Inuit
A member of a people living in Greenland and northernmost. Inuit is the plural of inuk, which means “person” in the Inuit language. |
iron pyrite
A mineral that looks similar to gold but has no value; also known as fool’s gold. |
isthmus
A narrow bridge of land connecting two larger landmasses. |
Jesuit
A member of a Roman Catholic religious order known for its educational and missionary work. |
keel
The V-shaped backbone of a ship. |
keelboat
A shallow, covered riverboat, generally used for freight, that is usually rowed or towed. |
lateen
A rig with a triangular sail hung from a yard fixed diagonally to the mast. |
latitude
Measurement of a point on the earth’s surface north or south of the equator. |
league
A distance equal to three miles. |
log
A written record of a journey; especially, the written record of a ship’s daily progress. |
longitude
Measurement of a point on the earth’s surface east or west of a given prime meridian. |
Louisiana Territory
The land west of the Mississippi River, encompassing the drainage basins of the Missouri and Arkansas Rivers, purchased by President Thomas Jefferson from France in 1803. |
magnetic storm
A major disturbance in the earth’s magnetic field. |
magnetosphere
A layer that surrounds a celestial object (such as Earth), that is dominated by the objects’s magnetic field, and within which highly charged particles are trapped. |
magnet stone
A naturally magnetic iron ore, also called magnetite. |
malaria
A fever caused by a parasite transmitted by the bite of the female anopheles mosquito. |
Mandan
A member of a Native American people related to the Sioux who lived along the Missouri River
between the Heart and Little Missouri Rivers. |
mantle
The area below the earth’s surface and above the core. |
Maya
A great civilization of southern Mexico, at its height around 800 CE. |
meltwater
Water that swells a river after the melting of snow and ice in mountainous regions near the river’s source. |
merchant marine
A nation’s commercial ships, as opposed to those used for military purposes.The merchant marine is in some nations privately owned and in others controlled by the government. |
meridian
An imaginary line, running from the North to the South Pole, used to indicate longitude. |
meteorology
The study of the weather, especially as a means of forecasting future weather conditions. |
micrometeorite
A tiny piece of space debris. |
midshipman
Temporary rank held by young men training to be naval officers. |
militia
An army unit formed of citizens, such as those used in early U.S. history by state governments. |
Milky Way
The galaxy of which Earth and its solar system are a part. |
missionary
One who works, usually in a foreign country, to spread a religious faith (especially Christianity) and to give humanitarian assistance. |
missionary school
School formed by Christian missionaries, in the Americas, China, or elsewhere, to teach the native inhabitants Western culture and Christian values. |
mission hospital
Hospital built and run by a Christian church group; its aims were to heal the sick and spread Christianity. |
module
A self-contained unit, as of a spacecraft. |
monopoly
Total control over the sale of a good or service in a given area. |
monsoon
A wind in southern Asia that blows from the northeast in winter and from the southwest in the summer, when it is accompanied by heavy rains. |
Moor
A member of a Muslim people of mixed North African, Berber, and Spanish descent who ruled a progressively smaller area of Spain from the tenth century through the fifteenth. |
mountain
man A man who worked as a hunter and trapper in the Rocky Mountains in the first half of the
nineteenth century, before American settlers moved into the West. |
multispectral scanner
A remote-sensing device that contains several sensors, each equipped to detect and receive signals from a particular band of the electromagnetic spectrum. |
mutiny
A revolt against authority, especially of a ship’s crew against its officers. |
negative
An image captured on chemically treated film or on a glass plate,with light and dark areas reversed, from which multiple positive photographic images may be produced. |
Norse
Referring generally to the people of Scandinavia (Norway, Sweden, and Denmark), especially during the years 790 to 1100. |
oceanography
Scientific study of the oceans. |
orbit
An object’s regularly repeated path around a star or planet. |
Oregon Trail
A two-thousand-mile (3,220 km) path from Missouri to western Oregon, used from 1841 to the 1880s by thousands of settlers moving west. |
Osage
A member of a Native American people that lived on the central Great Plains. |
Ottoman Empire
Empire of the Turks in western Asia and southwestern Europe, ruled from Istanbul from 1453 to 1922. |
outback
The wild inland territory of Australia. |
Pacific Northwest
The region of the present-day states of Washington and Oregon. |
parallel
An imaginary line, circling the globe parallel to the equator, used to indicate latitude. |
patent
A government license giving an inventor the exclusive right to make or sell an invention for a specified time. |
patron
Someone who financially supports another person or a project. |
Pawnee
A member of a Great Plains Indian people that lived in earth lodges along the Platte River, raised crops, and hunted buffalo. |
peninsula
A long, narrow piece of land that juts into the sea or a lake. |
philology
The scientific study of the history of languages and their relationship to one another, especially based on an analysis of texts. |
pilgrim
One who travels to visit a holy place. |
pillage
To plunder a place, that is, to remove, often violently, everything from it of material value. |
pinnace
A light sailing ship, often used to carry provisions or messages from one ship to another or from ship to shore. |
pioneer
The first person to attain a given goal, such as a feat of exploration, the settlement of a new territory, or the invention of a new technology. |
pirogue
A small boat, much like a canoe. |
planisphere
A representation of all or part of the spherical earth on a flat surface. |
polygamy
The practice of having more than one spouse. |
portage
The carrying of boats overland from one waterway to another. |
pressure ridge
A layer of ice forced up into a block by the pressure of surrounding ice. |
prevailing wind
The wind that predominates in a given area or at a given time. |
prime meridian
An imaginary line that runs from the North to the South Pole through Greenwich, England, and marks zero degrees longitude. |
principality
A state ruled by a prince. |
privateer
A privately owned ship hired by a government to attack and raid the ships of another country; also, a crew member of such a ship. |
projection
A method of displaying the curvature of the earth on a flat surface so that its physical features can be seen in true relation to one another. |
propeller
A spiral-shaped shaft driven by the engine to power a ship forward. |
Quaker
A member of the Society of Friends, a Christian sect founded in England in the seventeenth century that advocates a simple form of worship with no creeds, clergy, or formal church structure. |
quartz
A mineral of silicon dixode that takes a variety of forms, including gemstones, sandstone, and quartz sand (used in the manufacture of glass and ceramics). |
radar
A piece of technology, consisting of a radio transmitter and receiver, that emits radio waves and analyzes their echoes in order to identify and locate nearby objects or geographical features. |
radar mapping
A procedure for mapping an irregular surface from a distance or through obstacles, such as cloud or ice, by sending out radio waves and analyzing the returning echoes. |
radiate
To emit energy in the form of particles or rays. |
reconnaissance
A preliminary survey to gain information; during armed conflict, the gathering of information on the movement and position of an enemy. |
Reconquista
The centuries-long Spanish campaign to drive out the Moors, the descendants of the Muslims who had conquered Spain in the eighth century. |
recoup
To receive an amount of goods or money equivalent to an amount lost. |
reflector
A telescope that focuses light from distant objects through the use of mirrors. |
refractor
A telescope that focuses light from distant objects through the use of glass lenses. |
relativity
The theory, first proposed by Einstein, that equated matter and energy by means of the speed of light,which Einstein believed was constant. |
Renaissance
A cultural movement that began in the fourteenth century in Italy and lasted into the seventeenth.The Renaissance was marked by a flowering of artistic and literary achievement and a resurgence of interest in the values of ancient Greece and Rome. |
saga
An Icelandic literary form, dating from between 1100 and 1500, whose purpose was to praise the heroic deeds of historic or legendary figures and demonstrate the correct and honorable way to behave. |
samurai
A member of the warrior class in Japan that was dominant until the late nineteenth century. |
Sanskrit
An ancient language of the Indian subcontinent, considered the root of many modern European and Asian languages. |
satellite
An object, natural or artificial, that orbits a planet. |
scurvy
A serious disease caused by lack of vitamin C; its symptoms include bleeding and sponginess in the gums. |
Sea of Tranquillity
(In Latin,Mare Tranquilitatis) An area of the moon’s surface, sometimes visible from the earth as a dark spot in the moon’s northern hemisphere. Apollo 11’s lunar landing module, the Eagle, landed in the southwestern part of the Sea of Tranquillity on July 20, 1969. |
seaworthy
Referring to a ship that is strong and sturdy enough to be used safely for a sea voyage. |
seismic
Relating to earthquakes or other vibrations of the earth’s crust. |
sextant
An instrument used by seafarers and explorers to measure the height of the sun or a star above the horizon and thus give an estimation of one’s latitude. |
sheikh
Chief or leader of a group of Arabs. |
Sherpa
A member of a Tibetan people living in the Himalayas who provide support for mountain climbers and served the British army during the Second World War. |
Shoshone
A member of a Native American people who lived by hunting and gathering in the Great Basin region and the northern Rocky Mountains. |
Sioux
A member of a Native American people that lived on the northern Great Plains and as far east as southern Minnesota. |
Skraeling
A Norse word,meaning “wretch” or “ugly person,” used to describe the native North Americans the Icelandic settlers encountered. |
sled
A vehicle with runners instead of wheels that transports people and goods over snow-covered terrain or ice. |
sloop
A small, light, one-masted warship that usually carried between ten and eighteen cannons. |
solar flare
A sudden and intense burst of radioactive energy from a small area of the sun’s surface. |
solar system
A group of celestial bodies that are held by the magnetic attraction of the star they orbit. |
solar wind
The flow of radioactive particles from the sun. |
solstice
The time during summer and winter when the sun is vertically above the point that represents its farthest distance north or south of the equator. In the Northern Hemisphere the summer solstice is reached around June 21, and the winter solstice around December 22. |
sonar
A system that uses sound waves to detect objects underwater. |
space probe
An unmanned exploratory spacecraft. |
spar
Any of the tapered wooden poles used in the rigging of sails. |
spruce beer
A concoction,made from the boiled and fermented leaves and twigs of the American spruce (a tree of the pine family), that proved particularly effective at preventing scurvy during the exploration of North America. |
stade
An ancient unit of length used by Greek and Roman surveyors; the standard length of a stade is generally assumed to be six hundred feet (965 m), though many variations exist. |
stratosphere
A layer of the earth’s atmosphere that starts at about 26,000 feet (8 km) above the Poles and about 55,000 feet (17 km) above the equator and extends upward to around 165,000 feet (50 km). |
sultan
Title of a secular Muslim ruler, especially of the Ottoman Empire. |
sundial
An instrument that shows the time of day according to the shadow cast by a pointer known as a gnomon. |
sunspot
An area of the sun’s surface, one associated with strong magnetic activity, that appears darker because it is cooler than the surrounding area. |
synthesis
The combination of several concepts or compenent parts into a single entity. |
tack
To direct a ship into the wind along a zigzagging course by repeatedly adjusting the direction of the bow and the angle of the sails. |
Taino
A member of a Caribbean people native to the Greater Antilles (Puerto Rico, Hispaniola, Cuba, and Jamaica). |
taxonomy
Classification of plants and animals according to the natural relationship between them; also the study of different methods of classification. |
terrestrial
Of or relating to the earth. |
thermal imaging
A process for producing an image of an object or area of terrain using a special type of camera that is sensitive to minute differences in the heat that is emitted; an especially useful technique for taking pictures at night or in the absence of light. |
tidal bore
A high wall of water that rushes up certain narrow rivers during exceptionally high tides. |
Tlaxcalan
A member of an American Indian people native to an area of eastcentral Mexico around Tlaxcala. |
Tlaxcalan
A member of an American Indian people native to an area of eastcentral Mexico around Tlaxcala. |
topography
The physical features of an area, such as mountains, valleys, and streams; also, the study and mapping of such features. |
Totonac
A member of an Indian people native to an area of east-central Mexico. |
trading post
In North America, a settlement where European traders and Native American hunters exchanged goods for furs. |
transit
In astronomy, the passage of a planet across the face of the sun as viewed from the earth. |
treason
The crime of acting to overthrow or kill the monarch or government of the state to which the
criminal owes allegiance. |
trigonometry
The branch of mathematics concerned with the properties of triangles. |
Tuareg
A member of a nomadic people native to the central and western Sahara Desert region of North Africa. |
typhoid
A severe infection that causes a rash and stomach pains. |
ultraviolet
A form of short-wavelength radiation. |
viceroy
Ruler representing the authority of a king or queen in a colonial territory. |
Viking
A term, from a Norwegian word meaning both “pirate” and “warfare,” used generally to refer to a Scandinavian (someone from Norway, Sweden, or Denmark) during the years 790 to 1100; especially, any of the Norse raiders who plundered the coasts of western Europe in that period. |
vulcanized rubber
Rubber that has been treated with chemicals at a very high temperature to increase its usefulness. |
water clock
An instrument that measures time by the dripping of water from one container into another. |
Wichita
A member of an American Indian people native to the Great Bend area of the Arkansas River in present-day Kansas. |
wind drift
instrument An aerial navigation instrument that calculates the extent to which wind force is causing an aircraft to drift off course. |
wind vane
A simple device that indicates the direction in which the wind is blowing. |
yard
A spar crossing the mast to which sails are fixed. |
