twin crystal

Webster's Dictionary (GCIDE)

Twin \Twin\ (tw[i^]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. [1913 Webster]

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. [1913 Webster]

3.(Bot.) Double; consisting of two similar and corresponding parts. [1913 Webster]

4.(Crystallog.) Composed of parts united according to some definite law of twinning. See Twin, n., 4. [1913 Webster]

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 (Linnaea 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. [1913 Webster]