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

イ短調[itanchou] A minor
イ長調[ichouchou] A major
カーソル強調[kaasorukyouchou] cursored emphasis
ト短調[totanchou] G minor
ト長調[tochouchou] G major

ニ短調[nitanchou] D minor
ニ長調[nichouchou] D major
ハ短調[hatanchou] C minor
ハ長調[hachouchou] C major
ヘ短調[hetanchou] F minor