AB'AFT, adv. or prep. [Sax. eft or aeft, again. Hence efter or aefter, after, subsequent; Sax. aeftan, behind in place; to which word be is prefixed - beaeftan, behind, and this word is corrupted into abaft.]A sea-term signifying in or at the hinder part of a ship, or the parts which lie towards the stern; opposed to afore. Relatively it denotes further aft or towards the stern; as abaft the mainmast. Abaft the beam, is in that arch of the horizon which is between a line drawn at right angles with the keel, and the point to which the stern is directed. It is often contracted into aft.