Condominium and Flats

Condominium noun - Housing consisting of a complex of dwelling units (as an apartment house) in which each unit is individually owned.

Flats and condominium are semantically related. In some cases you can replace term "Flats" with "Condominium", this nouns are similar.

Flats noun - Footwear (shoes or slippers) with no heel (or a very low heel).

Condominium and flats are semantically related. Sometimes you can use "Condominium" instead a noun "Flats".