n The point of junction between two things, in particular a support, that abuts. (defdate|First attested in the mid 17th century.)
n (engineering|architecture) The solid portion of a structure that supports the lateral pressure of an arch or vault. (defdate|First attested in the mid 18th century.)
n (engineering) A construction that supports the ends of a bridge; a structure that anchors the cables on a suspension bridge. (defdate|First attested in the mid 18th century.)
n Something that abuts, or on which something abuts. (defdate|First attested in the mid 18th century.)