Merriam-Webster Online Dictionary
basement (noun)1.
the part of a building that is wholly or partly below ground level
2.
the ground floor facade or interior in Renaissance architecture
3.
the lowest or fundamental part of something , specifically the rocks underlying stratified rocks
4.
chiefly New England a toilet or washroom especially in a school
Merriam-Webster Online Thesaurus
basement (noun)1.
a room or set of rooms below the surface of the ground
SYNONIMS:
basementRELATED WORDS:
cellarage; bunker, crawlway, foundation, hold, vault; cyclone cellar, storm cellar2.
the lowest part, place, or point
SYNONIMS:
base, basement, foot, nadir, rock bottomRELATED WORDS:
basis, bed, bedrock, foundation, ground, groundwork, keystone, seat, underpinningNEAR ANTONYMS:
acme, apex, climax, crest, culmination, height, meridian, peak, pinnacle, summit, tip, tip-top, zenith