Definition of abutment

The lateral supporting structure of an arch, bridge or similar pressure; that part of a pier or wall from which an arch springs, specifically the support at either end of an arch, beam or bridge; that part of a structure which takes the thrust of a beam, arch, vault, truss or girder; the part of a bridge that supports the end of the span and prevents the bank from sliding under it; a foundation that carries gravity and also thrust loads.

(architecture) a masonry construction (usually curved) for spanning an opening and supporting the weight above it