\But"ment\, n. [Abbreviation of {Abutment}.] 1. (Arch.) A buttress of an arch; the supporter, or that part which joins it to the upright pier. 2. (Masonry) The mass of stone or solid work at the end of a bridge, by which the extreme arches are sustained, or by which the end of a bridge without arches is supported. {Butment cheek} (Carp.), the part of a mortised timber surrounding the mortise, and against which the shoulders of the tenon bear. --Knight.