Un"der*pin`ning (?), n. 1. The act of one who underpins; the act of supporting by stones, masonry, or the like.

2. (Arch.) (a) That by which a building is underpinned; the material and construction used for support, introduced beneath a wall already constructed. (b) The foundation, esp. of a frame house. [Local, U. S.]

Un"der*pin`ning (?), n. 1. The act of one who underpins; the act of supporting by stones, masonry, or the like.

2. (Arch.) (a) That by which a building is underpinned; the material and construction used for support, introduced beneath a wall already constructed. (b) The foundation, esp. of a frame house. [Local, U. S.]