cooptation (n.)

also co-optation, 1530s, "choice, selection, mutual choice, election to fill a vacancy" on a committee, board, or society, from Latin cooptationem (nominative cooptatio) "election," noun of action from past-participle stem of cooptare "to elect, to choose as a colleague or member of one's tribe," from assimilated form of com "with, together" (see com-) + optare "choose" (see option (n.)). Related: Cooptative.