How do you say "boss" in Japanese?

[yuiyoshida]

In Yakuza world : Oyabun 親分 (top level positon) or Kumichou
組長

In business world :jyoushi 上司
会長 kaichou｜the chairman (of the board of directors)
監査役 kansa yaku｜an auditor
経営者 keieisha｜a manager; the top management
最高業務責任者 saikou gyoumu sekininsha｜COO
最高経営責任者 saikou keiei sekininsha｜CEO
最高財務責任者 saikou zaimu sekininsya｜CFO
社長 shachou｜the president
常務取締役 jyoumu torishimariyaku｜a managing director
専務取締役 senmu torishimariyaku｜an executive director
相談役，顧問 komon｜a senior (corporate) adviser
代表取締役 daihyou torichimariyaku｜the representative director or CEO
副社長 huku shachou｜an executive vice-president
役員 yakuin，重役 jyuuyaku｜a director
係長 kakarichou｜a subsection chief
課長 kachou｜the head of a section [manager]
課長補佐 kachou hosa｜an assistant section manager
部長 buchou｜the general manager

complicated isn't it?!

[bluecollar2]

1. in my house we just said "mom"

But then my mother is Burmese...

[yuiyoshida]

2. Mother

okaasan ( お母さん ) is the honorific form of address, and you'd definitely use it to refer to someone else's mother. Formally, you wouldn't use it to refer to your own mother, but, in practice, at least some Japanese do. haha (はは ) would be used, formally, for your own mother, or in more casual speech.