一も二も無く[ichimonimonaku] unhesitatingly
一言二言[hitokotofutakoto] a word or two
一石二鳥[issekinichou] killing two birds with one stone
一二に及ばず[ichininioyobazu] right away
一姫二太郎[ichihimenitarou] It's good to have a girl first and then a boy

うり二つ[urifutatsu] as alike as two melons (two peas in a pod)
黄道十二宮[koudoujuunikyuu] twelve signs of the zodiac
二度[futatabi] again
最小二乗法[saishounijouhou] least-squares method
三十二分音符[sanjuunibuonpu] 32nd note

力瘤[chikarakobu] large biceps
力瘤を入れる[chikarakobuwoireru] to work earnestly
動脈瘤[doumyakuryuu] aneurysm
静脈瘤[joumyakuryuu] a varix
根瘤[konryuu] root nodule

瘤つき[kobutsuki] having a child (usu. from a former relationship)
一瘤駱駝[hitokoburakuda] dromedary
脳動脈瘤[noudoumyakukobu] cerebral aneurysm
腫瘤[shuryuu] lump

双峰駱駝[souhourakuda] two-humped camel
単峰駱駝[tanpourakuda] Arabian camel
駱駝[rakuda] camel
駝鳥[dachou] ostrich (Struthio camelus)
一瘤駱駝[hitokoburakuda] dromedary

駱駝色[rakudairo] camel color
二瘤駱駝[futakoburakuda] Bactrian camel (Camelus bactrianus)
駱駝虫[rakudamushi] inocelliid snakefly (any insect of family Inocelliidae)
アメリカ駝鳥[amerikadachou] rhea (Pterocnemia pennata)
鷸駝鳥[shigidachou] tinamou (any bird of family Tinamidae)

双峰駱駝[souhourakuda] two-humped camel
単峰駱駝[tanpourakuda] Arabian camel
駱駝[rakuda] camel
一瘤駱駝[hitokoburakuda] dromedary
駱駝色[rakudairo] camel color

二瘤駱駝[futakoburakuda] Bactrian camel (Camelus bactrianus)
駱駝虫[rakudamushi] inocelliid snakefly (any insect of family Inocelliidae)
駱駅[rakueki] constant stream of traffic
駱駝炭[rakudazumi] charcoal burned in an earthen kiln