伯父; 叔父さん
おじさん · ojisan · JLPT N5 · noun
uncle
👨 oji-san: oji (uncle) + san (Mr.) — literally Mr. Uncle
伯父 is a parent's older brother, 叔父 a younger one; both are read oji. Add the polite -san and it also covers any middle-aged man. Keep the i short: ojiisan with a long i means grandfather.