Synonyms and related words :
base, basement, basis, bearing wall, bed, bedding, bedrock, belly, best, bottom, bottom side, bottommost, breech, buttocks, cut, deepest, downside, floor, flooring, fond, footing, foundation, fundament, fundamental, giveaway, ground, grounds, groundwork, half-price, hardpan, lower side, lowest, lowest layer, lowest level, marked down, nether side, nethermost, nethermost level, pavement, principle, radical, reduced, riprap, rudiment, sacrificial, seat, sill, slashed, solid ground, solid rock, stereobate, stylobate, substratum, substruction, substructure, terra firma, underbelly, underbuilding, undercarriage, undergirding, underlayer, undermost, underneath, underpinning, underside, understruction, understructure