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

異類[irui] varieties
一類[ichirui] same kind
円虫類[enchuurui] round worms
塩類[enrui] salts
塩類溶液[enruiyoueki] saline

貝類[kairui] shellfish
柑橘類[kankitsurui] citrus fruits
希土類[kidorui] rare earth
魚貝類[gyokairui] marine products
魚類[gyorui] fish

伉配[kouhai] spouse

雙六[sugoroku] child's dice game

範疇[hanchuu] category
下位範疇化[kaihanchuuka] subcategorization
下位範疇化原理[kaihanchuukagenri] subcategorization principle
下位範疇化素性[kaihanchuukasosei] subcategorization feature

統語範疇[tougohanchuu] syntactic category
範疇部門[hanchuubumon] categorial component
範疇文法[hanchuubunpou] categorical grammar