basement
Concise Oxford English Dictionary © 2008 Oxford University Press:
basement/ˈbeɪsmənt/
▶noun
- 1 a room or floor which is partly or entirely below ground level.
- 2 Geology the oldest formation of rocks underlying a particular area.
– origin C18: prob. from archaic Du. basement ‘foundation’, perh. from Ital. basamento ‘column base’.
'basement' also found in these Oxford entries:

