early 15c., "to join" (transitive), from Latin copulatus, past participle of copulare "join together, couple, bind, link, unite," from copula "band, tie, link," from PIE *ko-ap-, from *ko(m)- "together" (see com-) + *ap- (1) "to take, reach" (see apt). Intransitive sense "to unite sexually" is attested from 1630s. Related: Copulated; copulating.

linking or connecting verb (especially "be"), word which expresses relation between subject and predicate, 1640s, from Latin copula "that which binds, rope, band, bond" (see copulate). Related: Copular.

"uniting, serving to couple," late 14c., from Late Latin copulativus, from copulat-, past-participle stem of Latin copulare "to join together, link, unite," from copula "a band, tie, link" (see copulate). Related: Copulatively.

late 14c., copulacioun, "a coupling, joining, uniting," from Latin copulationem (nominative copulatio) "a coupling, joining, connecting," noun of action from past-participle stem of copulare "join together, couple, bind, link, unite," from copula "band, tie, link" (see copulate). Specific sense of "sexual intercourse, coition" is from late 15c., and this became the main sense from 16c.

name for some types of freshwater terrapin in southern U.S., especially the common box-turtle, 1835 (first attested 1827 in phrase drunk as a cooter, but this perhaps is a colloquial form of unrelated coot), of uncertain origin, perhaps from obsolete verb coot "to copulate" (1660s), which is of unknown origin. The turtles are said to copulate for two weeks at a stretch.

c. 1200, "to link or connect, as one thing with another," from Old French copler "to couple, join together," from cople (see couple (n.)). Meaning "unite in marriage" is from mid-14c.; that of "embrace sexually, copulate" is from c. 1400. Related: Coupled; coupling.