n. [ L. ab + E. articulation : cf. F. abarticulation. See Article. ] (Anat.) Articulation, usually that kind of articulation which admits of free motion in the joint; diarthrosis. Coxe. [ 1913 Webster ]

a. Abbatial. [ Obs. ] [ 1913 Webster ]

a. Of or pertaining to the fir tree or its products; as, abietic acid, called also sylvic acid. Watts. [ 1913 Webster ]

a. (Biol.) Of or pertaining to abiogenesis. Ab`i*o*ge*net"ic*al*ly, adv. [1913 Webster]

n. [ L. abortus + caedere to kill. See Abort. ] (Med.) The act of destroying a fetus in the womb; feticide. [ archaic ] AS [ 1913 Webster ]

a. Pertaining to absolutism; absolutist. [ 1913 Webster ]

a. [ L. acatalecticus, Gr. &unr_;, not defective at the end; 'a priv. + &unr_; to cease. ] (Pros.) Not defective; complete; as, an acatalectic verse. -- n. A verse which has the complete number of feet and syllables. [ 1913 Webster ]

a. [ Gr. &unr_;. ] Incapable of being comprehended; incomprehensible. [ 1913 Webster ]

a. Pertaining to, or resembling, the acephalocysts. [ 1913 Webster ]

a. [ L. acetum vinegar, fr. acere to be sour. ] (Chem.) (a) Of a pertaining to vinegar; producing vinegar; producing vinegar; as, acetic fermentation. (b) Pertaining to, containing, or derived from, acetyl, as acetic ether, acetic acid. The latter is the acid to which the sour taste of vinegar is due. [ 1913 Webster ]

a. Of or pertaining to Acheron; infernal; hence, dismal, gloomy; moribund. [ 1913 Webster ]

adj. 1. of or pertaining to achondrite. [ WordNet 1.5 ]

2. chondritic [ WordNet 1.5 ]

adj. (Med.) of or pertaining to achondroplasia. [ WordNet 1.5 ]

a. [ Gr. 'achrw`matos colorless; 'a priv. + chrw^ma, chrw`matos, color: cf. F. achromatique. ] 1. (Opt.) Free from color; transmitting light without decomposing it into its primary colors. [ 1913 Webster ]

2. (Biol.) Uncolored; not absorbing color from a fluid; -- said of tissue. [ 1913 Webster ]

Achromatic lens (Opt.), a lens composed usually of two separate lenses, a convex and concave, of substances having different refractive and dispersive powers, as crown and flint glass, with the curvatures so adjusted that the chromatic aberration produced by the one is corrected by other, and light emerges from the compound lens undecomposed. --
Achromatic prism. See Prism. --
Achromatic telescope, or
microscope, one in which the chromatic aberration is corrected, usually by means of a compound or achromatic object glass, and which gives images free from extraneous color. [ 1913 Webster ]

adv. In an achromatic manner. [ 1913 Webster ]

n. Achromatism. [ 1913 Webster ]

adj. 1. of or pertaining to acidosis; suffering from acidosis. [ WordNet 1.5 ]

a. 1. Of or pertaining to aconite. [ 1913 Webster ]

2. (Chem.) Pert. to or designating a crystalline tribasic acid, C6H6O6, obtained from aconite and other plants. It is a carboxyl derivative of itaconic acid. Both the natural forma from plants and the form prepared chemically have the trans-configuration. It is used in the manufacture of itaconic acid (propylene dicarboxylic acid). MI11
Syn. -- 1-propene-1, 2, 3-tricarboxylic acid, equisetic acid, citridic acid, achilleic acid [ Webster 1913 Suppl. +PJC ]

a. [ F. acoustique, Gr. &unr_; relating to hearing, fr. &unr_; to hear. ] Pertaining to the sense of hearing, the organs of hearing, or the science of sounds; auditory. [ 1913 Webster ]

Acoustic duct, the auditory duct, or external passage of the ear. --
Acoustic telegraph, a telegraph making audible signals; a telephone. --
Acoustic vessels, brazen tubes or vessels, shaped like a bell, used in ancient theaters to propel the voices of the actors, so as to render them audible to a great distance. [ 1913 Webster ]

n. A medicine or agent to assist hearing. [ 1913 Webster ]

a. Of or pertaining to acoustics. [ 1913 Webster ]

adv. In relation to sound or to hearing. Tyndall. [ 1913 Webster ]

n. One versed in acoustics. Tyndall. [ 1913 Webster ]

n. [ Names of sciences in -ics, as, acoustics, mathematics, etc., are usually treated as singular. See -ics. ] (Physics.) The science of sounds, teaching their nature, phenomena, and laws. [ 1913 Webster ]

Acoustics, then, or the science of sound, is a very considerable branch of physics. Sir J. Herschel. [ 1913 Webster ]

☞ The science is, by some writers, divided, into diacoustics, which explains the properties of sounds coming directly from the ear; and catacoustica, which treats of reflected sounds or echoes. [ 1913 Webster ]

a. [ Gr. 'a priv. + &unr_; critical. ] (Med.) Having no crisis; giving no indications of a crisis; as, acritical symptoms, an acritical abscess. [ R. ] AS [ 1913 Webster ]

{ } a. [ Gr. &unr_;, fr. &unr_; to hear. ] Communicated orally; oral; -- applied to the esoteric teachings of Aristotle, those intended for his genuine disciples, in distinction from his exoteric doctrines, which were adapted to outsiders or the public generally. Hence: Abstruse; profound. [ 1913 Webster ]

a. [ Gr. &unr_;, fr. &unr_; to hear. ] Same as Acroamatic. [ 1913 Webster ]

a. [ Cf. F. acrobatique. ] Pertaining to an acrobat. [ 1913 Webster ]

-- Ac`ro*bat"ic*al*ly, adv. [1913 Webster]

a. [ Gr. 'a`kros extreme + &unr_; alone + &unr_; a letter. ] Having each verse begin with the same letter as that with which the preceding verse ends. [ 1913 Webster ]

pr>(&unr_;), n. [ Gr. &unr_;; &unr_; extreme + &unr_; order, line, verse. ] 1. A composition, usually in verse, in which the first or the last letters of the lines, or certain other letters, taken in order, form a name, word, phrase, or motto. [ 1913 Webster ]

2. A Hebrew poem in which the lines or stanzas begin with the letters of the alphabet in regular order (as Psalm cxix.). See Abecedarian. [ 1913 Webster ]

Double acrostic, a species of enigma, in which words are to be guessed whose initial and final letters form other words. [ 1913 Webster ]

{ } n. Pertaining to, or characterized by, acrostics. [ 1913 Webster ]

adv. After the manner of an acrostic. [ 1913 Webster ]

n. [ Gr. 'a`kros extreme + teley`th end. ] (Eccles.) The end of a verse or psalm, or something added thereto, to be sung by the people, by way of a response. [ 1913 Webster ]

a. [ Gr. 'akro`ths an extreme, fr. 'a`kros. ] 1. (Med.) Pertaining to or affecting the surface of the body. AS [ 1913 Webster ]

2. (Med.) Pertaining to acrotism. Dorland. [ AS ]

a. (Min.) Of the nature of, or containing, actinolite. [ 1913 Webster ]

adj. (Med.) Of or pertaining to actinomycosis. [ WordNet 1.5 ]

adj. 1. 1 advocating a cause or engaged in activism [ WordNet 1.5 ]

n. (Astron.) an optical system used in some telescopes since the 1980's which rapidly changes the shape of the primary reflecting mirror to adjust for distortions of light which are caused by atmospheric turbulence. By reducing the distortions caused by the atmosphere, telescopes fitted with such optics can achieve a higher resolving power than normal telescopes with static mirrors. [ PJC ]

a. [ Gr. 'adia`batos not passable; 'a priv. + dia` through + bai`nein to go. ] (Physics) Not giving out or receiving heat. -- Ad`i*a*bat`ic*al*ly, adv. [ Webster 1913 Suppl. ]

☞The adiabatic expansion of carbon dioxide from a compressed container causes the temperature of the gas to decrease rapidly below its freezing point, resulting in the familiar carbon dioxide “snow” emitted by carbon dioxide fire extinguishers. [ PJC. ]

Adiabatic line or
curve, a curve exhibiting the variations of pressure and volume of a fluid when it expands without either receiving or giving out heat. Rankine. [ 1913 Webster ]

a. Pertaining to matters indifferent in faith and practice. Shipley. [ 1913 Webster ]

a. [ L. adeps, adipis, fat + Gr. &unr_; to loose. ] (Chem.) Hydrolyzing fats; converting neutral fats into glycerin and free fatty acids, esp. by the action of an enzyme; as, adipolytic action. Contrast saponify, to hydrolyze fat by the action of an alkali. [ Webster 1913 Suppl. ]

adj. 1. of or pertaining to the adrenal cortex. [ WordNet 1.5 ]

adj. 1. stimulating or acting on the adrenal cortex [ WordNet 1.5 ]

n. 1. a growth hormone produced by the anterior pituitary gland; it stimulates the adrenal cortex.
Syn. -- adrenocorticotropic hormone, adrenocorticotrophic hormone, adrenocorticotrophin, corticotropin, corticotrophin, ACTH [ WordNet 1.5 ]

a. [ L. Adriaticus, Hadriaticus, fr. Adria or Hadria, a town of the Veneti. ] Of or pertaining to a sea so named, the northwestern part of which is known as the Gulf of Venice. [ 1913 Webster ]

adj. 1. of or pertaining to adventurism. [ WordNet 1.5 ]

a. Of or pertaining to aërolites; meteoric; as, aërolitic iron. Booth. [ 1913 Webster ]

{ } a. [ Cf. F. aéronauitique. ] Pertaining to aëronautics, or aërial sailing. [ 1913 Webster ]

n. The science or art of ascending and sailing in the air, as by means of a balloon; aërial navigation; ballooning. [ 1913 Webster ]

{ } a. [ Aëro- + Gr. &unr_;: cf. F. aérostatique. See Statical, Statics. ] 1. Of or pertaining to aërostatics; pneumatic. [ 1913 Webster ]

2. Aëronautic; as, an aërostatic voyage. [ 1913 Webster ]