bf[basement floor]

BF（Basement Floor) 指地下一層，負一樓。

base.ment
AHD:[b³s“m…nt]
D.J.[6beism*nt]
K.K.[6besm*nt]
n.（名詞）
The substructure or foundation of a building.
建築物的基礎、根基
The lowest habitable story of a building, usually below ground level.
地下室：可居住的最低的建築物樓層，通常在地平面以下
New England A public toilet, especially one in a school.