basement Meaning, Definition & Usage

  1. noun the lowermost portion of a structure partly or wholly below ground level; often used for storage
    cellar.
  2. noun the ground floor facade or interior in Renaissance architecture

WordNet

Base"ment noun
Etymology
F. soubassement. Of uncertain origin. Cf. Base, a., Bastion.
Definitions
  1. (Arch.) 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.

Webster 1913