bsmt.

Noun

basement (plural basements)

1. A floor of a building below ground level.
   • Turning back, then, toward the basement staircase, she began to grope her way through blinding darkness, but had taken only a few uncertain steps when, of a sudden, she stopped short and for a little stood like a stricken thing, quite motionless save that she quaked to her very marrow in the grasp...1914 November, Louis Joseph Vance, “An Outsider […]”, in Munsey’s Magazine, volume LIII, number II, New York, N.Y.: The Frank A[ndrew] Munsey Company, […], published 1915, →OCLC, chapter III...
2. A mass of igneous or metamorphic rock forming the foundation over which a platform of sedimentary rocks is laid.
3. (informal) Last place in a sports conference's standings.