[ beys-muh nt ]
/ ˈbeɪs mənt /


a story of a building, partly or wholly underground.
(in classical and Renaissance architecture) the portion of a building beneath the principal story, treated as a single compositional unit.
the lowermost portion of a structure.
the substructure of a columnar or arched construction.

Nearby words

  1. basel-stadt,
  2. baseless,
  3. baseline,
  4. baseliner,
  5. baseman,
  6. basement complex,
  7. basement membrane,
  8. baseness,
  9. basenji,
  10. baseplate

Origin of basement

First recorded in 1720–30; base1 + -ment Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for basement


/ (ˈbeɪsmənt) /


  1. a partly or wholly underground storey of a building, esp the one immediately below the main floorCompare cellar
  2. (as modifier)a basement flat
the foundation or substructure of a wall or building
geology a part of the earth's crust formed of hard igneous or metamorphic rock that lies beneath the cover of soft sedimentary rock, sediment, and soil
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for basement



"lowest story of a building except the cellar," 1730, from base (n.) + -ment.

Online Etymology Dictionary, © 2010 Douglas Harper