Ativan
1: tranquilizer (trade name Ativan) used to treat anxiety and tension and insomnia [syn: {lorazepam}]
Atlanta
1: state capital and largest city of Georgia; chief commercial center of the southeastern United States; was plundered and burned by Sherman's army during the American Civil War [syn: {capital of Geor...
Atlantic
1: relating to or bordering the Atlantic Ocean; "Atlantic currents" n : the 2nd largest ocean; separates North and South America on the west from Europe and Africa on the east [syn: {Atlantic Ocean}]
Atlantic bonito
1: medium-sized tuna-like food fish of warm Atlantic and Pacific waters; less valued than tuna [syn: {skipjack}, {Sarda sarda}]
Atlantic bottlenose dolphin
1: the most common dolphin of northern Atlantic and Mediterranean; often kept captive and trained to perform [syn: {Tursiops truncatus}]
Atlantic City
1: a city on the Atlantic shore in southeastern New Jersey; a resort and gambling center
Atlantic cod
1: one of the world's most important commercial fishes [syn: {Gadus morhua}]
Atlantic croaker
1: silvery-bodied with dark markings and tiny barbels [syn: {Micropogonias undulatus}]
Atlantic halibut
1: largest United States flatfish [syn: {Hippoglossus hippoglossus}]
Atlantic herring
1: important food fish; found in enormous shoals in the northern Atlantic [syn: {Clupea harengus harengus}]
Atlantic manta
1: largest manta (to 22 feet across wings); found worldwide but common in Gulf of Mexico and along southern coasts of United States; primarily oceanic [syn: {Manta birostris}]
Atlantic moonfish
1: any of several silvery marine fishes with very flat bodies [syn: {moonfish}, {horsefish}, {horsehead}, {horse-head}, {dollarfish}, {Selene setapinnis}]
Atlantic Ocean
1: the 2nd largest ocean; separates North and South America on the west from Europe and Africa on the east [syn: {Atlantic}]
Atlantic puffin
1: common puffin of the northern Atlantic [syn: {Fratercula arctica}]
Atlantic ridley
1: gray sea turtle of the Atlantic and Gulf coasts of North America [syn: {bastard ridley}, {bastard turtle}, {Lepidochelys kempii}]
Atlantic salmon
1: fatty pink flesh of fish from northern coastal Atlantic; usually marketed fresh 2: found in northern coastal Atlantic waters or tributaries; adults do not die after spawning [syn: {Salmo salar}]
Atlantic spiny dogfish
1: destructive dogfish of the Atlantic coastal waters of America and Europe; widely used in anatomy classes [syn: {Squalus acanthias}]
Atlantic Standard Time
1: standard time in the 4th time zone west of Greenwich, reckoned at the 60th meridian; used in Puerto Rico and the Virgin Islands and Bermuda and the Canadian Maritime Provinces [syn: {Atlantic Time}...
Atlantic Time
1: standard time in the 4th time zone west of Greenwich, reckoned at the 60th meridian; used in Puerto Rico and the Virgin Islands and Bermuda and the Canadian Maritime Provinces [syn: {Atlantic Stand...
Atlantic tripletail
1: tripletail found from Cape Cod to northern South America [syn: {Lobotes surinamensis}]
Atlantic walrus
1: a walrus of northern Atlantic and Arctic waters [syn: {Odobenus rosmarus}]
Atlantic white cedar
1: slow-growing medium-sized cedar of east coast of the United States; resembles American arborvitae [syn: {southern white cedar}, {coast white cedar}, {white cypress}, {white cedar}, {Chamaecyparis t...
Atlantides
1: (Greek mythology) group of 3 to 7 nymphs who guarded the golden apples that Gaea gave as a wedding gift to Hera [syn: {Hesperides}]
Atlantis
1: according to legend, an island in the Atlantic Ocean that Plato said was swallowed by an earthquake
Atlas
1: (Greek mythology) a Titan who was forced by Zeus to bear the sky on his shoulders 2: a collection of maps in book form [syn: {book of maps}, {map collection}] 3: the 1st cervical vertebra [syn: {at...
Atlas cedar
1: tall Algerian evergreen of Atlas mountains with blue-green leaves; widely planted as an ornamental [syn: {Cedrus atlantica}]
atlas moth
1: giant saturniid moth widespread in Asia; sometimes cultured for silk [syn: {Atticus atlas}]
Atlas Mountains
1: a mountain range in northern Africa between the Mediterranean and the Sahara Desert; extends from southwestern Morocco to northern Tunisia
atm
1: a unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade [syn: {standard atmosphere}, {atmosphere}, {standard pressure}] 2: a means o...
atmometer
1: an instrument that measures rate of evaporation of water [syn: {evaporometer}]
atmosphere
1: a particular environment or surrounding influence; "there was an atmosphere of excitement" [syn: {ambiance}, {ambience}] 2: a unit of pressure: the pressure that will support a column of mercury 76...
atmospheric
1: relating to or located in the atmosphere; "atmospheric tests" [syn: {atmospherical}]
atmospheric condition
1: the meteorological conditions: temperature and wind and clouds and precipitation; "they were hoping for good weather"; "every day we have weather conditions and yesterday was no exception" [syn: {w...
atmospheric state
1: the weather or climate at some place; "the atmosphere was thick with fog" [syn: {atmosphere}]
atmospheric static
1: a crackling or hissing noise cause by electrical interference [syn: {static}, {atmospherics}]
atmospherical
1: relating to or located in the atmosphere; "atmospheric tests" [syn: {atmospheric}]
atmospherics
1: a crackling or hissing noise cause by electrical interference [syn: {static}, {atmospheric static}]
atole
1: eaten as mush or as a thin gruel
atoll
1: an island consisting of a circular coral reef surrounding a lagoon
atom
1: (physics and chemistry) the smallest component of an element having the chemical properties of the element 2: (nontechnical usage) a tiny piece of anything [syn: {molecule}, {particle}, {corpuscle}...
atom bomb
1: a nuclear weapon in which enormous energy is released by nuclear fission (splitting the nuclei of a heavy element like uranium 235 or plutonium 239) [syn: {atomic bomb}, {A-bomb}, {fission bomb}, {...
atom smasher
1: a scientific instrument that increases the kinetic energy of charged particles [syn: {accelerator}, {particle accelerator}]
atom-bomb
1: bomb with atomic weapons [syn: {nuke}]
atomic
1: of or relating to or comprising atoms; "atomic structure"; "atomic hydrogen" 2: (weapons) deriving destructive energy from the release of atomic energy; "nuclear war"; "nuclear weapons"; "atomic b...
atomic bomb
1: a nuclear weapon in which enormous energy is released by nuclear fission (splitting the nuclei of a heavy element like uranium 235 or plutonium 239) [syn: {atom bomb}, {A-bomb}, {fission bomb}, {pl...
atomic clock
1: a timepiece that derives its time scale from the vibration of atoms or molecules
atomic cocktail
1: an oral dose of radioactive substance used in treatment and diagnosis of cancer
atomic energy
1: the energy released by a nuclear reaction [syn: {nuclear energy}]
Atomic Energy Commission
1: a former executive agency (from 1946 to 1974) that was responsible for research into atomic energy and its peacetime uses in the United States [syn: {AEC}]
atomic mass
1: (chemistry) the mass (in atomic mass units) of an isotope of an element
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atomic number
1: the order of an element in Mendeleyev's table of the elements; equal to the number of protons in the nucleus or electrons in the neutral state of an atom of an element
atomic number 1
1: a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe [syn: {hydrogen}, {H}]
atomic number 10
1: a colorless odorless gaseous element that give a red glow in a vacuum tube; one of the six inert gasses; occurs in the air in small amounts [syn: {neon}, {Ne}]
atomic number 100
1: a radioactive transuranic metallic element produced by bombarding plutonium with neutrons [syn: {fermium}, {Fm}]
atomic number 101
1: a radioactive transuranic element synthesized by bombarding einsteinium with alpha particles (Md is the current symbol for mendelevium but Mv was formerly the symbol) [syn: {mendelevium}, {Md}, {Mv...
atomic number 102
1: a radioactive transuranic element synthesized by bombarding curium with carbon ions; 7 isotopes are known [syn: {nobelium}, {No}]
atomic number 103
1: a radioactive transuranic element synthesized from californium [syn: {lawrencium}, {Lw}]
atomic number 104
1: a radioactive transuranic element which has been synthesized [syn: {rutherfordium}, {Rf}, {kurchatovium}, {Ku}, {unnilquadium}, {Unq}, {element 104}]
atomic number 105
1: a transuranic element that has not been found in nature [syn: {unnilquintium}, {unnilpentium}, {Unp}, {hahnium}, {element 105}]
atomic number 106
1: a transuranic element [syn: {unnilhexium}, {Unh}, {element 106}]
atomic number 107
1: a transuranic element that has not been found in nature [syn: {unnilseptium}, {Uns}, {element 107}]
atomic number 11
1: a silvery soft waxy metallic element of the alkali metal group; occurs abundantly in natural compounds (especially in salt water); burns with a yellow flame and reacts violently in water; occurs in...
atomic number 12
1: a light silver-white ductile bivalent metallic element; in pure form it burns with brilliant white flame; occurs naturally only in combination (as in magnesite and dolomite and carnallite and spine...
atomic number 13
1: a silvery ductile metallic element found primarily in bauxite [syn: {aluminum}, {aluminium}, {Al}]
atomic number 14
1: a tetravalent nonmetallic element; next to oxygen it is the most abundant element in the earth's crust; occurs in clay and feldspar and granite and quartz and sand; used as a semiconductor in trans...
atomic number 15
1: a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several al...
atomic number 16
1: an abundant tasteless odorless multivalent nonmetallic element; best known in yellow crystals; occurs in many sulphide and sulphate minerals and even in native form (especially in volcanic regions)...
atomic number 17
1: a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a...
atomic number 18
1: a colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere [syn: {argon}, {Ar}]
atomic number 19
1: a light soft silver-white metallic element of the alkali metal group; oxidizes rapidly in air and reacts violently with water; is abundant in nature in combined forms occurring in sea water and in ...
atomic number 2
1: a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas a...
atomic number 20
1: a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals [syn: {calcium}, {Ca}]
atomic number 21
1: a white trivalent metallic element; sometimes classified in the rare earth group; occurs in the Scandinavian mineral thortveitite [syn: {scandium}, {Sc}]
atomic number 22
1: a light strong gray lustrous corrosion-resistant metallic element used in strong light-weight alloys (as for airplane parts); the main sources are rutile and ilmenite [syn: {titanium}, {Ti}]
atomic number 23
1: a soft silvery white toxic metallic element used in steel alloys; it occurs in several complex minerals including carnotite and vanadinite [syn: {vanadium}, {V}]
atomic number 24
1: a hard brittle blue-white multivalent metallic element; resistant to corrosion and tarnishing [syn: {chromium}, {Cr}]
atomic number 25
1: a hard brittle gray polyvalent metallic element that resembles iron but is not magnetic; used in making steel; occurs in many minerals [syn: {manganese}, {Mn}]
atomic number 26
1: a heavy ductile magnetic metallic element; is silver-white in pure form but readily rusts; used in construction and tools and armament; plays a role in the transport of oxygen by the blood [syn: {i...
atomic number 27
1: a hard ferromagnetic silver-white bivalent or trivalent metallic element; a trace element in plant and animal nutrition [syn: {cobalt}, {Co}]
atomic number 28
1: a hard malleable ductile silvery metallic element that is resistant to corrosion; used in alloys; occurs in pentlandite and smaltite and garnierite and millerite [syn: {nickel}, {Ni}]
atomic number 29
1: a ductile malleable reddish-brown corrosion-resistant diamagnetic metallic element; occurs in various minerals but is the only metal that occurs abundantly in large masses; used as an electrical an...
atomic number 3
1: a soft silver-white univalent element of the alkali metal group; the lightest metal known; occurs in several minerals [syn: {lithium}, {Li}]
atomic number 30
1: a bluish-white lustrous metallic element; brittle at ordinary temperatures but malleable when heated; used in a wide variety of alloys and in galvanizing iron; it occurs as zinc sulphide in zinc bl...
atomic number 31
1: a rare silvery (usually trivalent) metallic element; brittle at low temperatures but liquid above room temperature; occurs in trace amounts in bauxite and zinc ores [syn: {gallium}, {Ga}]
atomic number 32
1: a brittle gray crystalline element that is a semiconducting metalloid (resembling silicon) used in transistors; occurs in germanite and argyrodite [syn: {germanium}, {Ge}]
atomic number 33
1: a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and r...
atomic number 34
1: a toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable gray metallike allotrope conducts electricity better in the light than in the dark and is u...
atomic number 35
1: a nonmetallic largely pentavalent heavy volatile corrosive dark brown liquid element belonging to the halogens; found in sea water [syn: {bromine}, {Br}]
atomic number 36
1: a colorless element that is one of the six inert gasses; occurs in trace amounts in air [syn: {krypton}, {Kr}]
atomic number 37
1: a soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and pollucite [syn: {rubidium}, {Rb}]
atomic number 38
1: a soft silver-white or yellowish metallic element of the alkali metal group; turns yellow in air; occurs in celestite and strontianite [syn: {strontium}, {Sr}]
atomic number 39
1: a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys [syn: {yttrium}, {Y}]
atomic number 4
1: a light strong brittle gray toxic bivalent metallic element [syn: {beryllium}, {Be}, {glucinium}]
atomic number 40
1: a lustrous gray strong metallic element resembling titanium; it is used in nuclear reactors as a neutron absorber; it occurs in baddeleyite but is obtained chiefly from zircon [syn: {zirconium}, {Z...
atomic number 41
1: a soft gray ductile metallic element used in alloys; occurs in niobite; formerly called columbium [syn: {niobium}, {Nb}]
atomic number 42
1: a polyvalent metallic element that resembles chromium and tungsten in its properties; used to strengthen and harden steel [syn: {molybdenum}, {Mo}]
atomic number 43
1: a crystalline metallic element not found in nature; occurs as one of the fission products of uranium [syn: {technetium}, {Tc}]
atomic number 44
1: a rare polyvalent metallic element of the platinum group; it is found associated with platinum [syn: {ruthenium}, {Ru}]
atomic number 45
1: a white hard metallic element that is one of the platinum group and is found in platinum ores; used in alloys with platinum [syn: {rhodium}, {Rh}]
atomic number 46
1: a silver-white metallic element of the platinum group that resembles platinum; occurs in some copper and nickel ores; does not tarnish at ordinary temperatures and is used (alloyed with gold) in je...
atomic number 47
1: a soft white precious univalent metallic element having the highest electrical and thermal conductivity of any metal; occurs in argentite and in free form; used in coins and jewelry and tableware a...
atomic number 48
1: a soft bluish-white ductile malleable toxic bivalent metallic element; occurs in association with zinc ores [syn: {cadmium}, {Cd}]
atomic number 49
1: a rare soft silvery metallic element; occurs in small quantities in sphalerite [syn: {indium}, {In}]
atomic number 5
1: a trivalent metalloid element; occurs both in a hard black crystal and in the form of a yellow or brown powder [syn: {boron}, {B}]
atomic number 50
1: a silvery malleable metallic element that resists corrosion; used in many alloys and to coat other metals to prevent corrosion; obtained chiefly from cassiterite where it occurs as tin oxide [syn: ...
atomic number 51
1: a metallic element having four allotropic forms; used in a wide variety of alloys; found in stibnite [syn: {antimony}, {Sb}]
atomic number 52
1: a brittle silver-white metalloid element that is related to selenium and sulfur; it is used in alloys and as a semiconductor; occurs mainly as tellurides in ores of copper and nickel and silver and...
atomic number 53
1: a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks) [syn: {...
atomic number 54
1: a colorless odorless inert gaseous element occurring in the earth's atmosphere in trace amounts [syn: {xenon}, {Xe}]
atomic number 55
1: a soft silver-white ductile metallic element (liquid at normal temperatures); the most electropositive and alkaline metal [syn: {cesium}, {caesium}, {Cs}]
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