basement, cellar - the lowermost portion of a structure partly or wholly below ground level; often used for storage

building, edifice - a structure that has a roof and walls and stands more or less permanently in one place; "there was a three-story building on the corner"; "it was an imposing edifice"

first floor, ground floor, ground level - the floor of a building that is at or nearest to the level of the ground around the building

attic, garret, loft - floor consisting of open space at the top of a house just below roof; often used for storage

loft - floor consisting of a large unpartitioned space over a factory or warehouse or other commercial space

mezzanine floor, mezzanine - intermediate floor just above the ground floor

structure, construction - a thing constructed; a complex construction or entity; "the structure consisted of a series of arches"; "she wore her hair in an amazing construction of whirls and ribbons"