MORTISE, noun mor'tis. A cut or hollow place made in timber by the augur and chisel, to receive the tenon of another piece of timber. MOR'TISE, verb transitive To cut or make a mortise in. 1. To join timbers by a tenon and mortise; as, to mortise a beam into a post, or a joist into a girder.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI