一挙両得[ikkyoryoutoku] killing two birds with one stone
一刀両断[ittouryoudan] cutting in two with a single stroke
一両[ichiryou] one vehicle
一両日[ichiryoujitsu] (a) day or two
一両年[ichiryounen] (a) year or two

賛否両論[sanpiryouron] the pros and cons
車両[sharyou] rolling stock
車両化[sharyouka] motorization
車両縦隊[sharyoujuutai] convoy
衆参両院[shuusanryouin] both houses of Parliament (Diet)

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

育ての親[sodatenooya] foster parents
育て親[sodateoya] foster parent
１等親[ittoushin] first-degree relative
仮親[karioya] adopted parents
近親[kinshin] near relative

近親婚[kinshinkon] consanguineous marriage
近親相姦[kinshinsoukan] incest
懇親[konshin] friendship
懇親会[konshinkai] friendly reunion
似非親[eseoya] distant disinterested parent