Formal address is "oto-san", I guess "chichi" is a more informal way to say it. Chichi is also slang for breasts. Strange but true. I guess written in kanji or hiragana it is very different despite sounding the same.<br/><br/>http://www.dicts.info/2/english-japanese_romaji.php?word=chichi&begin=Search<br/><br/>http://www.dicts.info/2/english-japanese_romaji.php?word=father&begin=Search<br/>