Fundament

n.	1.	Foundation.
	2.	(Anat.) The part of the body on which one sits; the buttocks; specifically (Anat.), the anus.

Noun	1.	fundament - the fundamental assumptions from which something is begun or developed or calculated or explained; "the whole argument rested on a basis of conjecture" Synonyms: cornerstone, groundwork, basis, foundation, base
	2.	fundament - the fleshy part of the human body that you sit on; "he deserves a good kick in the butt"; "are you going to sit on your fanny and do nothing?" Synonyms: arse, ass, behind, buns, buttocks, derriere, fanny, hind end, hindquarters, keister, nates, posterior, prat, rear end, tooshie, tush, seat, backside, bottom, butt, stern, rump, tail end, tail, can, bum, rear
	3.	fundament - lowest support of a structure; "it was built on a base of solid rock"; "he stood at the foot of the tower" Synonyms: understructure, groundwork, substructure, base, foundation, foot

backside, base, basement, basis, beam, bearing wall, bed, bedding, bedrock, behind, belly, bottom, bottom side, breech, buttocks, derriere, downside, floor, flooring, fond, footing, foundation, fundamental, ground, grounds, groundwork, hardpan, lower side, lowest layer, lowest level, nether side, nethermost level, pavement, posterior, principle, radical, rear, riprap, rock bottom, rudiment, rump, seat, sill, solid ground, solid rock, stereobate, stylobate, substratum, substruction, substructure, terra firma, underbelly, underbuilding, undercarriage, undergirding, underlayer, underneath, underpinning, underside, understruction, understructure