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

御祖父さん[ojiisan] grandfather
御祖母さん[obaasan] grandmother
遠祖[enso] forefathers
開祖[kaiso] (sect) founder
外祖父[gaisofu] maternal grandfather

共同祖界[kyoudousokai] international settlement
教祖[kyouso] founder of a religious sect
元祖[ganso] originator
お高祖頭巾[okosozukin] kerchief worn by women in former times in Japan in cold weather, covering the whole head (except eyes)
始祖[shiso] founder