{ } a. [ Gr. &unr_; unequal + &unr_; a turning, &unr_; to turn. ] (Physics) Not isotropic; having different properties in different directions; thus, crystals of the isometric system are optically isotropic, but all other crystals are anisotropic. [ 1913 Webster ]

n. (Naut.) A rope stitched to the edges of a sail to strengthen the sail. [ 1913 Webster ]

n. See Breastband. [ 1913 Webster ]

n. [ Gr. &unr_; color + &unr_; turn, rotation, &unr_; to turn. ] 1. (Physics) An instrument for exhibiting certain chromatic effects of light (depending upon the persistence of vision and mixture of colors) by means of rapidly rotating disks variously colored. [ 1913 Webster ]

2. A device in a magic lantern or stereopticon to produce kaleidoscopic effects. [ 1913 Webster ]

n. [ Gr. &unr_; in + &unr_; upright, correct + &unr_; to turn. ] An optical toy; a card on which confused or imperfect figures are drawn, but which form to the eye regular figures when the card is rapidly revolved. See Thaumatrope. [ 1913 Webster ]

‖n. [ L., fr. Gr. &unr_; reference, arbitration, fr. &unr_; to turn over, to give up, yield; 'epi` upon, over + &unr_; to turn. ] (Rhet.) A figure by which permission is either seriously or ironically granted to some one, to do what he proposes to do; e. g., “He that is unjust, let him be unjust still.” [ 1913 Webster ]

n. (Aut.) (a) The rope rigged below a yard, upon which men stand when reefing or furling; -- formerly called a horse. (b) That part of the boltrope to which the lower edge of a sail is sewed. [ 1913 Webster ]

n. [ F. héliotrope, L. heliotropium, Gr. &unr_;; &unr_; the sun + &unr_; to turn, &unr_; turn. See Heliacal, Trope. ] 1. (Anc. Astron.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line. [ 1913 Webster ]

2. (Bot.) A plant of the genus Heliotropium; -- called also turnsole and girasole. Heliotropium Peruvianum is the commonly cultivated species with fragrant flowers. [ 1913 Webster ]

3. (Geodesy & Signal Service) An instrument for making signals to an observer at a distance, by means of the sun's rays thrown from a mirror. [ 1913 Webster ]

4. (Min.) See Bloodstone (a). [ 1913 Webster ]

Heliotrope purple, a grayish purple color. [ 1913 Webster ]

n. The person at a geodetic station who has charge of the heliotrope. [ 1913 Webster ]

a. [ Hemi- + Gr. &unr_; to turn: cf. F. hémitrope. ] Half turned round; half inverted; (Crystallog.) having a twinned structure. [ 1913 Webster ]

n. That which is hemitropal in construction; (Crystallog.) a twin crystal having a hemitropal structure. [ 1913 Webster ]

n. [ Hydro-, 1 + Gr. &unr_; to turn, direct. ] A device for raising water by the direct action of steam; a pulsometer. [ 1913 Webster ]

n. [ Gr. &unr_; breadth + &unr_; to turn. ] (Anat.) One of a pair of a paired organs. [ 1913 Webster ]

n. (Physics) See Rheotrope. [ 1913 Webster ]

n. [ Gr. "rei^n to flow + &unr_;&unr_;&unr_; to turn.] (Elec.) An instrument for reversing the direction of an electric current. [Written also reotrope.] [1913 Webster]

n. [ Gr. sh^ma sign + tre`pein to turn. ] An instrument for signaling by reflecting the rays of the sun in different directions. Knight. [ 1913 Webster ]

n. [ Gr. qay^ma a wonder + tre`pein to turn. ] (Opt.) An optical instrument or toy for showing the persistence of an impression upon the eyes after the luminous object is withdrawn. [ 1913 Webster ]

☞ It consists of a card having on its opposite faces figures of two different objects, or halves of the same object, as a bird and a cage, which, when the card is whirled rapidly round a diameter by the strings that hold it, appear to the eye combined in a single picture, as of a bird in its cage. [ 1913 Webster ]

n. [ L. tropus, Gr. &unr_;, fr. &unr_; to turn. See Torture, and cf. Trophy, Tropic, Troubadour, Trover. ] (Rhet.) (a) The use of a word or expression in a different sense from that which properly belongs to it; the use of a word or expression as changed from the original signification to another, for the sake of giving life or emphasis to an idea; a figure of speech. (b) The word or expression so used. [ 1913 Webster ]

In his frequent, long, and tedious speeches, it has been said that a trope never passed his lips. Bancroft. [ 1913 Webster ]

☞ Tropes are chiefly of four kinds: metaphor, metonymy, synecdoche, and irony. Some authors make figures the genus, of which trope is a species; others make them different things, defining trope to be a change of sense, and figure to be any ornament, except what becomes so by such change. [ 1913 Webster ]

n. (Chem.) Any one of a series of artificial ethereal salts derived from the alkaloidal base tropine. [ 1913 Webster ]

n. [ Gr. &unr_; life + &unr_; turning, from &unr_; to turn. ] An optical toy, in which figures made to revolve on the inside of a cylinder, and viewed through slits in its circumference, appear like a single figure passing through a series of natural motions as if animated or mechanically moved. [ 1913 Webster ]