Webster's Unabridged Dictionary - Letter H

Webster's Unabridged Dictionary - Letter H - Page 59

Hydrostatician (n.) One who is versed or skilled in hydrostatics. [R.]

Hydrostatics (n.) (Physics) The branch of science which relates to the pressure and equilibrium of nonelastic fluids, as water, mercury, etc.; the principles of statics applied to water and other liquids.

Compare: Mechanics

Mechanics (n.) That science, or branch of applied mathematics, which treats of the action of forces on bodies.

Note: That part of mechanics which considers the action of forces in producing rest or equilibrium is called statics; that which relates to such action in producing motion is called dynamics. The term mechanics includes the action of forces on all bodies, whether solid, liquid, or gaseous. It is sometimes, however, and formerly was often, used distinctively of solid bodies only: The mechanics of liquid bodies is called also hydrostatics, or hydrodynamics, according as the laws of rest or of motion are considered. The mechanics of gaseous bodies is called also pneumatics. The mechanics of fluids in motion, with special reference to the methods of obtaining from them useful results, constitutes hydraulics.

Animal mechanics (Physiol.), That portion of physiology which has for its object the investigation of the laws of equilibrium and motion in the animal body. The most important mechanical principle is that of the lever, the bones forming the arms of the levers, the contractile muscles the power, the joints the fulcra or points of support, while the weight of the body or of the individual limbs constitutes the weight or resistance.

Applied mechanics, The principles of abstract mechanics applied to human art; also, the practical application of the laws of matter and motion to the construction of machines and structures of all kinds.

Orbital mechanics, The principles governing the motion of bodies in orbit around other bodies under gravitational influence, such as artificial Earth satellites.

Hydrostatics (n.) Study of the mechanical properties of fluids that are not in motion.

Hydrosulphate (n.) (Chem.) Same as Hydrosulphurent.

Hydrosulphide (n.) (Chem.) One of a series of compounds, derived from hydrogen sulphide by the replacement of half its hydrogen by a base or basic radical; as, potassium hydrosulphide, KSH. The hydrosulphides are analogous to the hydrates and include the mercaptans.

Hydrosulphite (n.) (Chem.) A saline compound of hydrosulphurous acid and a base. [R.]

Hydrosulphuret (n.) (Chem.) A hydrosulphide. [Archaic]

Hydrosulphureted (a.) (Chem.) Combined with hydrogen sulphide.

Hydrosulphuric (a.) (Chem.) Pertaining to, or derived from, hydrogen and sulphur; as, hydrosulphuric acid, a designation applied to the solution of hydrogen sulphide in water.

Hydrosulphurous (a.) (Chem.) Pertaining to, or designating, an acid obtained by the reduction of sulphurous acid. See Hyposulphurous acid, under Hyposulphurous.

Hydrotellurate (n.) (Chem.) A salt formed by the union of hydrotelluric acid and the base.

Hydrotelluric (a.) (Chem.) Formed by hydrogen and tellurium; as, hydrotelluric acid, or hydrogen telluride.

Hydrothecae (n. pl.) of Hydrotheca.

Hydrothecas (n. pl.) of Hydrotheca.

Hydrotheca (n.) (Zool.) One of the calicles which, in some Hydroidea (Thecaphora), protect the hydrants. See Illust. of Hydroidea, and Campanularian.

Hydrotherapy (n.) (Med.) See Hydropathy.

Hydrotherapy (n.) The internal and external use of water in the treatment of disease [syn: hydropathy, hydrotherapy].

Hydrothermal (a.) Of or pertaining to hot water; -- used esp. with reference to the action of heated waters in dissolving, redepositing, and otherwise producing mineral changes within the crust of the globe.

Hydrothermal (a.) Of, pertaining to, or using the hot waters or steam found at special locations within the earth's crust; as, hydrothermal power generation.

Hydrothorax (n.) (Med.) An accumulation of serous fluid in the cavity of the chest.

Hydrothorax (n.) Accumulation of fluid in the pleural cavity (the space between the lungs and the walls of the chest) often resulting from disease of the heart or kidneys.

Hydrotic (a.) Causing a discharge of water or phlegm.

Hydrotic (n.) (Med.) A hydrotic medicine.

Hydrotical (a.) Hydrotic.

Hydrotrope (n.) A device for raising water by the direct action of steam; a pulsometer.

Hydrotropic (a.) (Bot.) Turning or bending towards moisture, as roots.

Hydrotropism (n.) (Bot.) A tendency towards moisture.

Hydrotropism (n.) (Bot.) In a broader sense, any curvature or turning induced in certain growing plant organs under the influence of moisture.

Note: When the movement is toward the moisture, as is the case in most roots, the phenomenon is called positive hydrotropism; when away from the moisture, as in the case of hyphae of certain fungi, negative hydrotropism.

Hydrous (a.) Containing water; watery.

Hydrous (a.) (Chem.) Containing water of hydration or crystallization.

Hydrous (a.) Containing combined water (especially water of crystallization as in a hydrate) [syn: hydrous, hydrated] [ant: anhydrous].

Hydroxanthane (n.) (Chem.) A persulphocyanate. [Obs.]

Hydroxanthic (a.) (Chem.) Persulphocyanic.

Hydroxide (n.) (Chem.) A hydrate; a substance containing hydrogen and oxygen, made by combining water with an oxide, and yielding water by elimination. The hydroxides are regarded as compounds of hydroxyl, united usually with basic element or radical; as, calcium hydroxide ethyl hydroxide.

Hydroxide (n.) A compound of an oxide with water [syn: hydroxide, hydrated oxide].

Hydroxide (n.) A chemical compound containing the hydroxyl group.

Hydroxy- () (Chem.) A combining form, also used adjectively, indicating hydroxyl as an ingredient.

Hydroxy acid (Chem.), An organic acid, having (besides the hydroxyl group of the carboxyl radical) an alcoholic hydroxyl group, and thus having the qualities of an alcohol in addition to its acid properties; as, lactic and tartaric acids are hydroxy acids.

Hydroxychloroquine (n.) Anti-inflammatory drug (trade name Plaquenil) used in the treatment of rheumatoid arthritis and malaria and lupus erythematosus [syn: hydroxychloroquine, Plaquenil].

Hydroxychloroquine (n.) 氫氧奎寧、羥氯奎寧 A drug derived from quinolone that is taken orally in the form of its sulfate C18H26ClN3O·H2SO4 to treat malaria, rheumatoid arthritis, and lupus erythematosus.

Hydroxyl (n.) (Chem.) A compound radical, or unsaturated group, HO, consisting of one atom of hydrogen and one of oxygen. It is a characteristic part of the hydrates, the alcohols, the oxygen acids, etc.

Hydroxyl (n.) The monovalent group -OH in such compounds as bases and some acids and alcohols [syn: hydroxyl, hydroxyl group, hydroxyl radical].

Hydroxylamine (n.) (Chem.) A nitrogenous, organic base, NH2.OH, resembling ammonia, and produced by a modified reduction of nitric acid. It is usually obtained as a volatile, unstable solution in water. It acts as a strong reducing agent.

Hydrozoa (n. pl.) (Zool.) The Acalephae; one of the classes of coelenterates, including the Hydroidea, Discophora, and Siphonophora.

Hydrozoon (n.; pl. L. Hydrozoa) [NL.] (Zool.) One of the Hydrozoa.

Compare: Molluscoidea

Molluscoidea, () Including Brachiopoda and Bryozoa. Mollusca, including Cephalopoda, Gastropoda, Pteropoda, Scaphopoda, Lamellibranchiata or Acephala. Echinodermata, including Holothurioidea, Echinoidea, Asterioidea, Ophiuroidea, and Crinoidea. C[oe]lenterata, including Anthozoa or Polyps, Ctenophora, and Hydrozoa or Acalephs. Spongiozoa or Porifera, including the sponges. Protozoa, including Infusoria and Rhizopoda. For definitions, see these names in the Vocabulary. Animalcular

Hydrozoa (n.) Coelenterates typically having alternation of generations; hydroid phase is usually colonial giving rise to the medusoid phase by budding: hydras and jellyfishes [syn: Hydrozoa, class Hydrozoa].

Hydrozoal (a.) (Zool.) Of or pertaining to the Hydrozoa.

Hydrozoa (n. pl.) (Zool.) The Acaleph[ae]; one of the classes of c[oe]lenterates, including the Hydroidea, Discophora, and Siphonophora.

Hydrozoa (n. pl.) of Hydrozoon.

Hydrozoons (n. pl.) [NL.] (Zool.) of Hydrozoon.

Hydrozoon (n.) [NL.] (Zool.) One of the Hydrozoa.

Compare: Molluscoidea

Protozoa, including Infusoria and Rhizopoda. For definitions, see these names in the Vocabulary. Animalcular

Molluscoidea (n. pl.) (Zool.) A division of Invertebrata which includes the classes Brachiopoda and Bryozoa; -- called also Anthoid Mollusca.

Note: Originally the Tunicata were included under Molluscoidea, from which they are known to differ widely in structure and embryology. Molluscoidea were formerly considered a subdivision of Mollusca, but they are now known to have more relationship with Annelida than with Mollusca.

Hydrozona (n.) Colonial coelenterates having the polyp phase dominant [syn: hydroid] [also: hydrozoa(pl)].

Hydrozoa, () See hydrozoan.

Hydruret (n.) (Chem.) A binary compound of hydrogen; a hydride. [Obs.]

Hydrus (n.) (Astron.) A constellation of the southern hemisphere, near the south pole.

Hydrus (n.) A constellation in the southern hemisphere near the south celestial pole.

Hye (n. & v.) See Hie. [Obs.] -- Chaucer.

Hyemal (a.) Belonging to winter; done in winter. -- Sir T. Browne.

Hyemate (v. i.) To pass the winter. [Obs. & R.]

Hyemation (n.) The passing of a winter in a particular place; a wintering.

Hyemation (n.) The act of affording shelter in winter. [Obs.]

Hyen (n.) A hyena. [Obs.] -- Shak.

Hyenas (n. pl.) of Hyena.

Hyena (n.) (Zool.) Any carnivorous mammal of the family Hyaenidae, of which three living species are known. They are large and strong, but cowardly. They feed chiefly on carrion, and are nocturnal in their habits. [Written also hy[ae]na.]

Syn: hyaena.

Note: The striped hyena ({Hy[ae]na striata) inhabits Southern Asia and a large part of Africa. The brown hyena ({Hy[ae]na brunnea), and the spotted hyena ({Crocuta maculata), are found in Southern Africa. The extinct cave hyena ({Hy[ae]na spel[ae]a) inhabited England and France.

Cave hyena. See under Cave.

Hyena dog (Zool.), A South African canine animal ({Lycaon venaticus), which hunts in packs, chiefly at night. It is smaller than the common wolf, with very large, erect ears, and a bushy tail. Its color is reddish or yellowish brown, blotched with black and white. Called also hunting dog.

Hyetal (a.) Of or pertaining to rain; descriptive of the distribution of rain, or of rainy regions.

Hyetograph (n.) A chart or graphic representation of the average distribution of rain over the surface of the earth.

Hyetographic (a.) Of or pertaining to to hyetography.

Hyetography (n.) The branch of physical science which treats of the geographical distribution of rain.

Hygeia (n.) (Classic Myth.) The goddess of health, daughter of Esculapius.

Hygeia (n.) (Greek mythology) The goddess of health; daughter of Aesculapius and sister of Panacea.

Hygeian (a.) Relating to Hygeia, the goddess of health; of or pertaining to health, or its preservation.

Hygeist (n.) One skilled in hygiena; a hygienist.

Hygieist (n.) A hygienist.

Hygiene (n.) That department of sanitary science which treats of the preservation of health, esp. of households and communities; a system of principles or rules designated for the promotion of health.

Compare: Regimen

Regimen (n.) Orderly government; system of order; adminisration. -- Hallam.

Regimen (n.) Any regulation or remedy which is intended to produce beneficial effects by gradual operation; esp. (Med.), a systematic course of diet, etc., pursed with a view to improving or preserving the health, or for the purpose of attaining some particular effect, as a reduction of flesh; -- sometimes used synonymously with hygiene.

Regimen (n.) (Gram.) (a) A syntactical relation between words, as when one depends on another and is regulated by it in respect to case or mood; government.

Regimen (n.) (Gram.) (b) The word or words governed.

Hygiene (n.) A condition promoting sanitary practices; "personal hygiene".

Hygiene (n.) The science concerned with the prevention of illness and maintenance of health [syn: hygiene, hygienics].

Hygienic (a.) 衛生（學）的；保健的 Of or pertaining to health or hygiene; sanitary.

Hygienic (a.) Tending to promote or preserve health; "hygienic habits like using disposable tissues"; "hygienic surroundings with plenty of fresh air" [syn: hygienic, hygienical].

Hygienics (n.) The science of health; hygiene.

Hygienics (n.) The science concerned with the prevention of illness and maintenance of health [syn: hygiene, hygienics].

Hygienism (n.) Hygiene.

Hygienist (n.) One versed in hygiene.

Hygienist (n.) A medical specialist in hygiene.

Hygiology (n.) A treatise on, or the science of, the preservation of health. [R.]

Hygrine (n.) (Chem.) An alkaloid associated with cocaine in coca leaves ({Erythroxylon coca), and extracted as a thick, yellow oil, having a pungent taste and odor.

Hygrodeik (n.) (Physics) A form of hygrometer having wet and dry bulb thermometers, with an adjustable index showing directly the percentage of moisture in the air, etc.

Hygrodeik (n.) A wet and dry bulb hygrometer.

Hygrograph (n.) (Physics) An instrument for recording automatically the variations of the humidity of the atmosphere.

Hygrology (n.) (Med.) The science which treats of the fluids of the body.

Hygrometer (n.) (Physics) An instrument for measuring the degree of moisture of the atmosphere.

Daniell's hygrometer, A form of hygrometer consisting of a bent glass tube terminating in two bulbs, the one covered with muslin, the other of black glass, and containing ether and a thermometer. Ether being poured on the muslin, the black ball, cooled by the evaporation of the ether within, is soon covered with dew; at this moment, the inclosed thermometer gives the dew-point, and this, compared with the reading of one in the air, determines the humidity. Hygrometric

Hygrometer (n.) Measuring instrument for measuring the relative humidity of the atmosphere.

Hygrometric (a.) Alt. of Hygrometrical.

Hygrometrical (a.) Of or pertaining to hygrometry; made with, or according to, the hygrometer; as, hygrometric observations.

Hygrometrical (a.) Readily absorbing and retaining moisture; as, hygrometric substances, like potash.

Hygrometry (n.) (Physics) That branch of physics which relates to the determination of the humidity of bodies, particularly of the atmosphere, with the theory and use of the instruments constructed for this purpose.

Hygrophanous (a.) Having such a structure as to be diaphanous when moist, and opaque when dry.

Hygrophthalmic (a.) (Anat.) Serving to moisten the eye; -- sometimes applied to the lachrymal ducts.

Hygroplasm (n.) (Biol.) The fluid portion of the cell protoplasm, in opposition to stereoplasm, the solid or insoluble portion. The latter is supposed to be partly nutritive and partly composed of idioplasm.

Hygroscope (n.) (Physics) An instrument which shows whether there is more or less moisture in the atmosphere, without indicating its amount.

Hygroscope (n.) Hygrometer that shows variations in the relative humidity of the atmosphere.

Hygroscopic (a.) Of or pertaining to, or indicated by, the hygroscope; not readily manifest to the senses, but capable of detection by the hygroscope; as, glass is often covered with a film of hygroscopic moisture.

Hygroscopic (a.) Having the property of readily inbibing moisture from the atmosphere, or of the becoming coated with a thin film of moisture, as glass, etc.

Hygroscopic (a.) Absorbing moisture (as from the air).

Hygroscopicity (n.) (Bot.) The property possessed by vegetable tissues of absorbing or discharging moisture according to circumstances.

Hygrostatics (n.) The science or art of comparing or measuring degrees of moisture. -- Evelyn.

Compare: Haik

Haik (n.) A large piece of woolen or cotton cloth worn by Arabs as an outer garment. [Written also hyke.] -- Heyse.

Hyke (n.) See Haik, and Huke.

Huke (n.) An outer garment worn in Europe in the Middle Ages. [Written also heuk and hyke.] [Obs.] -- Bacon.

Hylaeosaur (n.) Alt. of Hylaeosaurus.

Hylaeosaurus (n.) (Paleon.) A large Wealden dinosaur from the Tilgate Forest, England. It was about twenty feet long, protected by bony plates in the skin, and armed with spines.

Hylarchical (a.) Presiding over matter. [Obs.] -- Hallywell.

Hyleosaur (n.) Same as Hylaeosaur.

Hylic (a.) Of or pertaining to matter; material; corporeal; as, hylic influences.

Hylicist (n.) A philosopher who treats chiefly of matter; one who adopts or teaches hylism.

Hylism (n.) (Metaph.) A theory which regards matter as the original principle of evil.

Hylobate (n.) (Zool.) Any species of the genus Hylobates; a gibbon, or long-armed ape. See Gibbon.

Hylodes (n.) (Zool.) The piping frog ({Hyla Pickeringii), a small American tree frog, which in early spring, while breeding in swamps and ditches, sings with high, shrill, but musical, notes.

Hyloism (n.) Same as Hylotheism.

Hyloist (n.) Same as Hylotheist.

Hylopathism (n.) The doctrine that matter is sentient. -- Krauth-Fleming.

Hylopathist (n.) One who believes in hylopathism.

Hylophagous (a.) (Zool.) Eating green shoots, as certain insects do.

Hylotheism (n.) The doctrine of belief that matter is God, or that there is no God except matter and the universe; pantheism. See Materialism.

Hylotheist (n.) One who believes in hylotheism.

Hylozoic (a.) Of or pertaining to hylozoism.

Hylozoism (n.) The doctrine that matter possesses a species of life and sensation, or that matter and life are inseparable. [R.] -- Cudworth.

Hylozoist (n.) A believer in hylozoism. -- A. Tucker.

Hymar (n.) (Zool.) The wild ass of Persia.

Hymen (n.) (Anat.) 【解】處女膜 A fold of muscous membrane often found at the orifice of the vagina in virgins; the vaginal membrane.

It is usually torn by sexual intercourse.

Hymen (n.) (Class Myth.) 海曼（希臘、羅馬神話中的婚姻之神）；（h-）【古】【詩】婚姻；婚禮之歌 A fabulous deity; according to some, the son of Apollo and Urania, according to others, of Bacchus and Venus. He was the god of marriage, and presided over nuptial solemnities.

Till Hymen brought his love-delighted hour, There dwelt no joy in Eden's rosy bower. -- Campbell.

[previous page] [Index] [next page]