h

(thermodynamics) a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure; "enthalpy is the amount of energy in a system capable of doing mechanical work" ; the 8th letter of the Roman alphabet ; the constant of proportionality relating the energy of a photon to its frequency; approximately 6.626 x 10^-34 joule-second ; a unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second ; 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 ;

h-bomb

a nuclear weapon that releases atomic energy by union of light (hydrogen) nuclei at high temperatures to form helium ;

h. g. wells

prolific English writer best known for his science-fiction novels; he also wrote on contemporary social problems and wrote popular accounts of history and science (1866-1946) ;

h. h. munro

British writer of short stories (1870-1916) ;

h. j. eysenck

a British psychologist (born in Germany) noted for his theories of intelligence and personality and for his strong criticism of Freudian psychoanalysis ;

h. l. mencken

United States journalist and literary critic (1880-1956) ;

h. pylori

the type species of genus Heliobacter; produces urease and is associated with several gastroduodenal diseases (including gastritis and gastric ulcers and duodenal ulcers and other peptic ulcers) ;

h.m.s. bounty

a ship of the British navy; in 1789 part of the crew mutinied against their commander William Bligh and set him afloat in an open boat ;

h.p.

a unit of power equal to 746 watts ;

h2o

binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; widely used as a solvent ;

ha

(astronomy) the angular distance of a celestial point measured westward along the celestial equator from the zenith crossing; the right ascension for an observer at a particular location and time of day ;

ha'p'orth

the amount that can be bought for a halfpenny ;

ha'penny

an English coin worth half a penny ;

ha-ha

a ditch with one side being a retaining wall; used to divide lands without defacing the landscape ; a loud laugh that sounds like a horse neighing ;

haart

a combination of protease inhibitors taken with reverse transcriptase inhibitors; used in treating AIDS and HIV ;

haastia

genus of New Zealand mat-forming herbs or subshrubs: vegetable sheep ;

haastia pulvinaris

cushion-forming New Zealand herb having leaves densely covered with tawny hairs ;

habacuc

an Old Testament book telling Habakkuk's prophecies ;

habakkuk

an Old Testament book telling Habakkuk's prophecies ; a Hebrew minor prophet ;

habanera

a Cuban dance in duple time ; music composed in duple time for dancing the habanera ;

habeas corpus

the civil right to obtain a writ of habeas corpus as protection against illegal imprisonment ; a writ ordering a prisoner to be brought before a judge ;

habenaria

chiefly terrestrial orchids with tubers or fleshy roots often having long slender spurs and petals and lip lobes; includes species formerly placed in genus Gymnadeniopsis ;

habenaria albiflora

bog orchid of eastern North America with a spike of pure white fringed flowers ;

habenaria bifolia

south European orchid having fragrant greenish-white flowers; sometimes placed in genus Habenaria ;

habenaria chlorantha

south European orchid with dark green flowers that are larger and less fragrant than Platanthera bifolia; sometimes placed in genus Habenaria ;

habenaria dilatata

orchid with spikes of many fragrant white flowers on erect leafy stems; of wet or boggy ground through most of the West and northern North America ;

habenaria elegans

slender inland rein orchid similar to coastal rein orchid but with pale greenish-yellow flowers ;

habenaria fimbriata

North American orchid similar to Habenaria psycodes with larger paler flowers ;

habenaria greenei

stout orchid of central California to northern Washington having racemes of white fragrant bilaterally symmetrical flowers ;

habenaria hookeri

a long-spurred orchid with base leaves and petals converging under the upper sepal ;

habenaria lacera

fringed orchid of the eastern United States having a greenish flower with the lip deeply lacerate ;

habenaria leucophaea

orchid of boggy or wet lands of north central United States having racemes of very fragrant creamy or greenish white flowers ;

habenaria nivea

slender fringed orchid of eastern North America having white flowers ;

habenaria orbiculata

orchid having a raceme of large greenish-white flowers on a single flower stalk growing between two elliptic or round basal leaves lying on the ground; from northern Oregon and Montana across Canada to the eastern United States ;

habenaria peramoena

orchid of northeastern and alpine eastern North America closely related to the purple fringed orchids but having rosy-purple or violet flowers with denticulate leaf divisions ;

habenaria psycodes

North American orchid with clusters of fragrant purple fringed flowers ;

habenaria unalascensis

similar to coastal rein orchid but with smaller flowers; Alaska to Baja California and east to the Dakotas and Colorado ;

haber

German chemist noted for the synthetic production of ammonia from the nitrogen in air (1868-1934) ;

haber-bosch process

an industrial process for producing ammonia from nitrogen and hydrogen by combining them under high pressure in the present of an iron catalyst ;

haber process

an industrial process for producing ammonia from nitrogen and hydrogen by combining them under high pressure in the present of an iron catalyst ;