Definition of basement :
The outer wall of the ground story of a building, or of a part of that story, when treated as a distinct substructure. ( See Base, n., 3 ( a).) Hence: The rooms of a ground floor, collectively.
bottom (part of speech: noun)
- It is a low, damp basement her home. - "Humanity in the City", E. H. Chapin.
- It was necessary at night, with the Bartons asleep in the basement like a family in a vault, but it was just the same when they were all on duty, as at the present moment. - "The Crime Doctor", Ernest William Hornung.
- And then: Here's the stair: follow it down until you get to the basement. - "The Honorable Senator Sage-Brush", Francis Lynde.