御兄さん[oniisan] older brother
御兄ちゃん[oniichan] familiar form of "older brother"
御兄弟[gokyoudai] siblings
家兄[kakei] (my) elder brother
雅兄[gakei] polite word in letter to friend

義兄[gikei] brother-in-law
兄さん[niisan] older brother
兄嫁[aniyome] elder brother's wife
兄貴[aniki] one's senior

御祖父さん[ojiisan] grandfather
御父さん[otossan] father
異父[ifu] same mother, different father
家父長制[kafuchousei] patriarchal authority
外祖父[gaisofu] maternal grandfather

岳父[gakufu] (man's) father-in-law
杜父魚[tofugyo] sculpin (any fish of family Cottidae, inc. the bullheads and the miller's-thumb)
義父[gifu] father-in-law
教父[kyoufu] godfather
継父[keifu] stepfather