一元[ichigen] unitary
一元化[ichigenka] unification
一元的[ichigenteki] monistic
一元論[ichigenron] monism
一次元[ichijigen] one dimensional

一新紀元[isshinkigen] new era
隠元[ingen] beans
隠元豆[ingenmame] common bean (Phaseolus vulgaris)
家元[iemoto] head of a school (of music, dance)
火の元[hinomoto] origin of fire

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