Family relations - Part 1

One of my favorite and funniest scene in One Piece is when Garp, Luffy’s grandfather told him he actually met his father in Loguetown.  Luffy was actually surprised that he actually had a father?!!

In the video, Sanji said that Luffy’s grandfather is a big shot, 偉いさん or えらいさん (eraisan). Grandfather is お爺さん or おじいさん (ojiisan) when referring to someone else’s grandfather, while referring to one’s own grandfather is 祖父 or そふ (sofu).  However, お爺さん can be used when addressing one’s own grandfather.  Though when Luffy and his brothers are still young, they always called and referred Garp as じじ (jiji), which actually means old geezer (please don’t use じじ to address an older man).  お爺さん can also be used to refer to any male senior citizens.  While talking about grandfather, we might as well know that grandmother is お婆さん or おばあさん (obaasan) and 祖母 or そぼ (sobo), and the usage is similar to that of grandfather.  A grandchild is 孫 or まご (mago).

Monkey D. Dragon, Luffy's father

Luffy’s father was revealed to be the notorious revolutionary, 革命 or かくめい (kakumei), Monkey D. Dragon, who is infamously well-known among everybody except for Luffy himself.  When referring to someone else’s father, お父さん or おとうさん (otousan) is used, while referring to one’s own father, 父 or ちち (chichi) is used, while お父さん is also used when addressing one’s own father.  Similarly お母さん or おかあさん (okaasan) is used to refer to someone's mother or when addressing one's own mother, while 母 or はは (haha) for reference to one's own mother.  A son is 息子 or むすこ (musuko) or sometimes shortened to just こ (ko) when speaking informally, while a daughter is 娘 or むすめ (musume).

To summarize:

Kanji	Hiragana	Romaji	English
お爺さん	おじいさん	Ojisan	When referring to someone’s grandfather or when addressing one’s own grandfather
お婆さん	おばあさん	Obasan	When referring to someone’s grandmother or when addressing one’s own grandmother
お父さん	おとうさん	Otousan	When referring to someone’s father or when addressing one’s own father
お母さん	おかあさん	Okaasan	When referring to someone’s mother or when addressing one’s own mother
祖父	そふ	Sofu	When referring to own grandfather
祖母	そぼ	Sobo	When referring to own grandmother
父	ちち	Chichi	When referring to own father
母	はは	Haha	When referring to own mother
孫	まご	Mago	Grandchild
息子	むすこ	Musuko	Son
娘	むすめ	Musume	Daughter
	じじ	Jiji	Old geezer
偉いさん	えらいさん	Eraisan	Big shot
革命	かくめい	Kakumei	Revolution

Hope you learn Japanese well while enjoying the show.