Definition of twin
(Entry 1 of 3)
1a
: either of two offspring produced in the same pregnancy
2
: one of two persons or things closely related to or resembling each other
3
: a compound crystal composed of two adjoining crystals or parts of crystals of the same kind that share a common plane of atoms
twin
adjective
Definition of twin (Entry 2 of 3)
twin
verb
twinned; twinning
Definition of twin (Entry 3 of 3)
1
: to bring forth twins
2
of a crystal
: to grow in a compound form with two adjoining sections that share a common plane of atoms
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Merriam-Webster unabridged
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The first known use of twin was in the 14th century
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