From WordNet (r) 3.0 (2006):
fundament
n 1: the fundamental assumptions from which something is begun
or developed or calculated or explained; "the whole
argument rested on a basis of conjecture" [syn: basis,
base, foundation, fundament, groundwork,
cornerstone]
2: 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?" [syn: buttocks, nates,
arse, butt, backside, bum, buns, can,
fundament, hindquarters, hind end, keister,
posterior, prat, rear, rear end, rump, stern,
seat, tail, tail end, tooshie, tush, bottom,
behind, derriere, fanny, ass]
3: lowest support of a structure; "it was built on a base of
solid rock"; "he stood at the foot of the tower" [syn:
foundation, base, fundament, foot, groundwork,
substructure, understructure]