English and Irish, from a Roman family name, Terentius, which is the form used for Terence in old documents in Latin, with appropriate case endings.

Anglicized form of the Irish Gaelic name Toirdhealbhach, "instigator". [See also Turley.]

The assumed pet name Terry [q.v.] actually predates Terence and was derived in the Middle Ages from Germanic sources, introduced into Britain by the Normans