Underpinning

·noun The foundation, ·esp. of a frame house.

II. Underpinning ·p.pr. & ·vb.n. of Underpin.

III. Underpinning ·noun The act of one who underpins; the act of supporting by stones, masonry, or the like.

IV. Underpinning ·noun That by which a building is underpinned; the material and construction used for support, introduced beneath a wall already constructed.