Definition of underpinning :
1. of Underpin
2. That by which a building is underpinned; the material and construction used for support, introduced beneath a wall already constructed.
3. The act of one who underpins; the act of supporting by stones, masonry, or the like.
4. The foundation, esp. of a frame house.
feature, framework, keystone, foot, ground, footing, warp, over, supporting structure, fundament, burning issue/question, priority, bedrock, scaffold, root, element, essence, warp and woof, gantry, reinforcement, brace, mount, spur, cornerstone, foundation, key, mounting, rafter, shore, seat, frame, bed, core, bottom, stanchion, staple, base, basis, groundwork, joist, stay, substratum, concern
support (part of speech: noun)
supporting (part of speech: verb)
- An old ramshackle house, which Tom thought might once have been a boathouse, stood near, the water lapping its underpinning. - "Tom Slade Motorcycle Dispatch Bearer", Percy Keese Fitzhugh.
- I noticed, what is common in the country, that an underpinning of boards had been placed around the foundation at the distance of a foot, the space within being filled with earth. - "Nooks and Corners of the New England Coast", Samuel Adams Drake.
- The defective underpinning had, however, been replaced or strengthened, and he expected that Kerr would test it soon. - "The Girl From Keller's Sadie's Conquest", Harold Bindloss.