"abound, swarm, be prolific," Old English teman (Mercian), tieman (West Saxon) "beget, give birth to, bring forth, produce, propagate," from Proto-Germanic *tau(h)mjan (denominative), from PIE root *deuk- "to lead." Related to team (n.) in its now-obsolete Old English sense of "family, brood of young animals." The meaning "abound, swarm" is first recorded 1590s, on the notion of "be full of as if ready to give birth." Related: Teemed; teeming.