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

於多福[otafuku] homely woman (esp. one with a small low nose, high flat forehead, and bulging cheeks)
圧倒的多数[attoutekitasuu] overwhelming numbers
一妻多夫[issaitafu] polyandry
一番多い[ichibanooi] most numerous
一夫多妻[ipputasai] polygamy

引く手数多[hikuteamata] being very popular
過多[kata] excess
幾多[ikuta] many
ご多忙中[gotabouchuu] in the midst of your work (often used as a formal phrase in business letters, etc.)
好事魔多し[koujimaooshi] Lights are usually followed by shadows