- a partly or wholly underground storey of a building, esp the one immediately below the main floor
Compare cellar - (as modifier): a basement flat
- the foundation or substructure of a wall or building
WordReference Random House Learner's Dictionary of American English © 2026
base•ment /ˈbeɪsmənt/USA pronunciation
n. [countable]
WordReference Random House Unabridged Dictionary of American English © 2026- a floor or story of a building that is partly or completely underground.
base•ment
(bās′mənt),USA pronunciation n.
- a story of a building, partly or wholly underground.
- Architecture(in classical and Renaissance architecture) the portion of a building beneath the principal story, treated as a single compositional unit.
- Architecturethe lowermost portion of a structure.
- Architecturethe substructure of a columnar or arched construction.
- base1 + -ment 1720–30
Collins Concise English Dictionary © HarperCollins Publishers::
basement /ˈbeɪsmənt/ n
'basement' also found in these entries (note: many are not synonyms or translations):
area
- boiler room
- cellar
- dunny
- subbasement
- areaway
- bargain basement
- basement complex
- basement membrane
- below stairs
- box sill
- Bsmt
- center
- counterfort
- flood
- fornicate
- freeze
- low-rent
- L sill
- walkout
- wet
- semibasement
- stand
- suck
- superstructure