Twin (tw&ibreve_;n), a. [OE. twin double, AS. getwinne two and two, pl., twins; akin to D. tweeling a twin, G. zwilling, OHG. zwiniling, Icel. tvennr, tvinnr, two and two, twin, and to AS. twi- two. See Twice, Two.] 1. Being one of two born at a birth; as, a twin brother or sister.
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2. Being one of a pair much resembling one another; standing in the relation of a twin to something else; -- often followed by to or with. Shak.
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3. (Bot.) Double; consisting of two similar and corresponding parts.
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4. (Crystallog.) Composed of parts united according to some definite law of twinning. See Twin, n., 4.
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Twin boat, or Twin ship (Naut.), a vessel whose deck and upper works rest on two parallel hulls. -- Twin crystal. See Twin, n., 4. -- Twin flower (Bot.), a delicate evergreen plant (Linnæa borealis) of northern climates, which has pretty, fragrant, pendulous flowers borne in pairs on a slender stalk. -- Twin-screw steamer, a steam vessel propelled by two screws, one on either side of the plane of the keel.
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Twin (?), v. i. [imp. & p. p. Twinned (?); p. pr. & vb. n. Twinning.] 1. To bring forth twins. Tusser.
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2. To be born at the same birth. Shak.
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Twin, v. i. To depart from a place or thing. [Obs.] “Ere that we farther twin.” Chaucer.
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