n. 1. One of two produced at a birth, especially by an animal that ordinarily brings forth but one at a birth; -- used chiefly in the plural, and applied to the young of beasts as well as to human young. [ 1913 Webster ]

2. pl. (Astron.) A sign and constellation of the zodiac; Gemini. See Gemini. [ 1913 Webster ]

3. A person or thing that closely resembles another. [ 1913 Webster ]

4. (Crystallog.) A compound crystal composed of two or more crystals, or parts of crystals, in reversed position with reference to each other. [ 1913 Webster ]

☞ The relative position of the parts of a twin may be explained by supposing one part to be revolved 180° about a certain axis (called the twinning axis), this axis being normal to a plane (called the twinning plane) which is usually one of the fundamental planes of the crystal. This revolution brings the two parts into parallel position, or vice versa. A contact twin is one in which the parts are united by a plane surface, called the composition face, which is usually the same as the twinning plane. A penetration twin is one in which the parts interpenetrate each other, often very irregularly. Twins are also called, according to form, cruciform, geniculated, etc. [ 1913 Webster ]

v. t. 1. To cause to be twins, or like twins in any way. Shak. [ 1913 Webster ]

Still we moved
Together, twinned, as horse's ear and eye. Tennyson. [ 1913 Webster ]

2. To separate into two parts; to part; to divide; hence, to remove; also, to strip; to rob. [ Obs. ] [ 1913 Webster ]

The life out of her body for to twin. Chaucer. [ 1913 Webster ]

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 ]

v. i. [ imp. & p. p. Twinned p. pr. & vb. n. Twinning. ] 1. To bring forth twins. Tusser. [ 1913 Webster ]

2. To be born at the same birth. Shak. [ 1913 Webster ]

v. i. To depart from a place or thing. [ Obs. ] “Ere that we farther twin.” Chaucer. [ 1913 Webster ]

a. Born at the same birth. [ 1913 Webster ]

v. i. 1. To mutually twist together; to become mutually involved. [ 1913 Webster ]

2. To wind; to bend; to make turns; to meander. [ 1913 Webster ]

As rivers, though they bend and twine,
Still to the sea their course incline. Swift. [ 1913 Webster ]

3. To turn round; to revolve. [ Obs. ] Chapman. [ 1913 Webster ]

4. To ascend in spiral lines about a support; to climb spirally; as, many plants twine. [ 1913 Webster ]

v. t. [ imp. & p. p. Twined p. pr. & vb. n. Twining. ] [ OE. twinen, fr. AS. twīn a twisted thread; akin to D. twijnen to twine, Icel. & Sw. tvinna, Dan. tvinde. See Twine, n. ] 1. To twist together; to form by twisting or winding of threads; to wreathe; as, fine twined linen. [ 1913 Webster ]

2. To wind, as one thread around another, or as any flexible substance around another body. [ 1913 Webster ]

Let me twine
Mine arms about that body. Shak. [ 1913 Webster ]

3. To wind about; to embrace; to entwine. [ 1913 Webster ]

Let wreaths of triumph now my temples twine. Pope. [ 1913 Webster ]

4. To change the direction of. [ Obs. ] Fairfax. [ 1913 Webster ]

5. To mingle; to mix. [ Obs. ] Crashaw. [ 1913 Webster ]

n. [ AS. twīn, properly, a twisted or double thread; akin to D. twijn, Icel. tvinni; from twi-. See Twice, and cf. Twin. ] 1. A twist; a convolution. [ 1913 Webster ]

Typhon huge, ending in snaky twine. Milton. [ 1913 Webster ]

2. A strong thread composed of two or three smaller threads or strands twisted together, and used for various purposes, as for binding small parcels, making nets, and the like; a small cord or string. [ 1913 Webster ]

3. The act of twining or winding round. J. Philips. [ 1913 Webster ]

Twine reeler, a kind of machine for twisting twine; a kind of mule, or spinning machine. [ 1913 Webster ]

n. (Bot.) Any plant which twines about a support. [ 1913 Webster ]