From Latin 'copula' (a bond, tie), via Old French — originally the link joining two things, then the paired things themselves.
Two people or things of the same sort considered together; a pair.
From Old French 'cople,' from Latin 'copula' meaning 'a bond, link, tie,' from 'co-' (together) + 'apere' (to fasten). Originally referred to the bond joining two things, then to the pair itself. Key roots: co- (Latin: "together"), apere (Latin: "to fasten").