Lewis & Short

abdĭcātĭo, ōnis, f. [abdĭco], a renouncing, disowning.

    1. 1. Jurid. t. t.: hereditatis, Cod. Just. 6, 31, 6: liberorum, disinheriting, ib. 6, 8, 47; Quint. 7, 4, 27; 3, 6, 77; 7, 1, 15; Plin. 7, 45, 46, § 150 al.; cf. Dirksen, Versuch., etc., Leipz. 1823, p. 62 sq.
    2. * 2. Polit. t. t., a renunciation of an office, abdication: dictaturae, Liv. 6, 16 fin.