I. ˈtwin adjective
Etymology: Middle English, from Old English twinn twofold, double, two by two; akin to Old High German zwin al born a twin, zwini ling twin, Old Norse tvinnr, tvennr two by two, in pairs, Old English twēgen, twā, tū two — more at two
1.
a. : born with one other at the same birth
a twin brother
a twin lamb
b. : born as a pair at one birth
twin girls
2.
a. : made up of two similar, related, or connected members or parts : double
meet this twin (not alternative) responsibility — H.M.Wriston
this is the first half of the Crisis Question, this time a twin question — Hazel Sullivan
b. : paired in a close or necessary relationship : matching
the twin threats of war and inflation — New Republic
c. : having or consisting of two identical units
d.
(1) : constituting two similar, closely associated, or otherwise paired persons, topics, or objects
twin waiting rooms — American Guide Series: New York City
two girls in twin yellow dresses — Scott Fitzgerald
the twin realms of tactics and strategy — S.L.A.Marshall
(2) : being one of a pair of similar or associated persons or things
across the bay lies its twin city
3. : formed by twinning of crystals
II. noun
( -s )
Etymology: Middle English, from Old English ge twinn; akin to Old English twinn twofold — more at twin I
1.
a. : either of two offspring produced at a birth especially in a species that ordinarily brings forth but one at a birth — see identical twin
b. twins plural , usually capitalized : gemini 1
2. : one of two persons or things closely related to or resembling each other
a powder compact that was the twin of the one the old guy had found — Hartley Howard
3. : a pair of offspring that are twins
he was one of a twin
4. or twin crystal : a compound crystal composed of two or more crystals or parts of crystals of the same kind that are grown together in a specific manner so that there is at least one plane and the direction perpendicular thereto that are related in the same way to the crystallographic axes of both parts of the twin
5. : a well drilled on the same location as an existing oil well or gas well to tap a different producing formation
an oil well may have four or five twins
III. verb
( twinned ; twinned ; twinning ; twins )
Etymology: Middle English twinnen, from twin, adjective & noun
transitive verb
1. Scotland : to put asunder : cause to be separated : part , divide , sunder
2. : to bear as twins
3.
a. : to bring together in close association : link , couple , join
whose name will always remain twinned with that of the … institute — B.R.Redman
b. : duplicate , match , parallel
sat at a spacious desk whose highly polished surface twinned his upper half in reverse — V.V.Nabokov
intransitive verb
1. Scotland : to go apart : separate
2. : to bring forth twins
3. archaic : to be born at the same birth with another
4. obsolete : to become coupled or combined : join
5. : to grow as a twin crystal