option n.

"take to one's self, make one's own by selection," c. 1500, a back-formation from adoption or else from Old French adopter (14c.) or directly from Latin adoptare "chose for oneself, take by choice, select, adopt," especially "to take into a family, adopt as a child," from ad "to" (see ad-) + optare "choose, wish, desire" (see option (n.)).

Originally in English of friends, fathers, citizens, etc., as well as children. The specific sense of "to legally take as one's own child" and that of "to embrace, espouse" a practice, method, etc. are from c. 1600. Related: Adopted; adopting.

mid-14c., adopcioun, "action of taking (a child) as one's own; condition of being adopted," from Old French adopcion or directly from Late Latin adoptionem (nominative adoptio) "a taking as one's child," shorter form of adoptatio, noun of action from past-participle stem of Latin adoptare "chose for oneself, take by choice, select, adopt," especially "to take into a family, adopt as a child," from ad "to" (see ad-) + optare "choose, wish, desire" (from PIE root *op- (2) "to choose;" see option (n.)).