Noun
1. the fundamental assumptions from which something is begun or developed or calculated or explained;
"the whole argument rested on a basis of conjecture"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?"3. lowest support of a structure;
"it was built on a base of solid rock""he stood at the foot of the tower"