copulate (v.) Look up copulate at Dictionary.com
early 15c., "to join," 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" + *ap- (1) "to take, reach" (see apt). Sexual sense attested from 1630s. Related: Copulated; copulating.