2. a masonry support that touches and directly receives thrust or pressure of an arch or bridge;
The Collaborative International Dictionary of English v.0.48:
Abutment \A*but"ment\ ([.a]*b[u^]t"ment), n.
1. State of abutting.
2. That on or against which a body abuts or presses; as
(a) (Arch.) The solid part of a pier or wall, etc., which
receives the thrust or lateral pressure of an arch,
vault, or strut. --Gwilt.
(b) (Mech.) A fixed point or surface from which resistance
or reaction is obtained, as the cylinder head of a
steam engine, the fulcrum of a lever, etc.
(c) In breech-loading firearms, the block behind the
barrel which receives the pressure due to recoil.
WordNet (r) 3.0 (2006):
n 1: point of contact between two objects or parts
2: a masonry support that touches and directly receives thrust
or pressure of an arch or bridge