I. ˈtwin noun
Etymology: Middle English, from twin twofold
Date: 14th century
1.
a. : either of two offspring produced at a birth
b. plural , capitalized : Gemini
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·ship -ˌship noun
II. verb
( twinned ; twin·ning )
Date: 14th century
transitive verb
1. : to bring together in close association : couple
2. : duplicate , match
intransitive verb
1. : to bring forth twins
2. : to grow as a twin crystal
III. adjective
Etymology: Middle English, twofold, double, from Old English twinn; akin to Old Norse tvinnr two by two, Old English twā two
Date: 1593
1. : born with one other or as a pair at one birth
my twin brother
twin girls
2.
a. : made up of two similar, related, or connected members or parts : double
b. : paired in a close or necessary relationship : matching
c. : having or consisting of two identical units
d. : being one of a pair