What would mean year 532 "U.C" for a Roman, for instance?

That should be equal to 222 BC and means 532 years from the founding of Rome "anno urbis conditae" AUC.

Pretty much so.The Romans dated the years from the founding of Rome( ab urbe condita or urbis conditae) as you mentioned, which correspond to 753 b.c.
So 753 minus 532 = 221. Good answer Kwll. .