suteren

1. semi-basement; lower ground floor
   Stan je u suterenu, pa je malo vlažan. — The flat is in the semi-basement, so it's a bit damp.
   Cena je niža jer je stan u suterenu. — The price is lower because the flat is on the lower ground floor.

Do not confuse with "podrum" (cellar, usually not lived in) and "prizemlje" (ground floor).