from
The Collaborative International Dictionary of English v.0.48
Butment \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.
[1913 Webster]
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.
[1913 Webster]
{Butment cheek} (Carp.), the part of a mortised timber
surrounding the mortise, and against which the shoulders
of the tenon bear. --Knight.
[1913 Webster] Butt