双節棍[nunchaku] nunchaku (two linked fighting sticks)
一双[issou] pair (esp. of folding screens)
一卵性双生児[ichiranseisouseiji] identical twins
双紙[soushi] written work (esp. a bound text, as opposed to a scroll)
自己双対[jikosoutsui] self dual

双刃[moroha] double-edged
双暗車[souansha] twin propellers
双殻類[soukakurui] bivalves
双眼[sougan] both eyes

御呪い[omajinai] good luck charm
呪い[noroi] curse
呪い[majinai] charm
呪う[norou] to curse
呪禁[jugon] vanquishing monsters, spirits, etc. with charms

呪術[jujutsu] magic
呪縛[jubaku] curse
呪文[jumon] spell
呪物[jubutsu] fetish
呪物崇拝[jubutsusuuhai] fetishism