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

一元[ichigen] unitary
一元化[ichigenka] unification
一元的[ichigenteki] monistic
一元論[ichigenron] monism
一次元[ichijigen] one dimensional

一新紀元[isshinkigen] new era
隠元[ingen] beans
隠元豆[ingenmame] common bean (Phaseolus vulgaris)
家元[iemoto] head of a school (of music, dance)
火の元[hinomoto] origin of fire

列記[rekki] list
一列[ichiretsu] (a) row
下り列車[kudariressha] trains going away from the capital
逆行列[gyakugyouretsu] inverse matrix
区間列車[kukanressha] local train

系列[keiretsu] series
系列化[keiretsuka] putting in order
後列[kouretsu] rear
行列[gyouretsu] line
行列式[gyouretsushiki] determinant

其れ形[sorenari] in itself
悪形[akugata] villain's part
為替手形[kawasetegata] draft
異形[igyou] fantastic
井戸屋形[idoyakata] well roof

印形[ingyou] seal
雲形[kumogata] cloud formations
円錐形[ensuikei] cone
円筒形[entoukei] cylindrical
凹形[oukei] concavity

向きに成る[mukininaru] to become serious
持て成し[motenashi] entertainment
成吉思汗[jingisukan] Japanese mutton and vegetable dish
亜成層圏[aseisouken] substratosphere
成す[nasu] to build up

成手[narite] candidate
育成栽培[ikuseisaibai] vegetable and fruit growing
一気呵成[ikkikasei] finishing writing, work, etc. at a stroke (stretch)
化成[kasei] change
化成工業[kaseikougyou] chemical industry

機関[karakuri] mechanism
アナログ計算機[anarogukeisanki] analog computer
エンジン発動機[enjinhatsudouki] engine
サーボ機構[saabokikou] servomechanism
シフト演算機構[shifutoenzankikou] shift arithmetic unit

ジェット機[jettoki] jet aeroplane
弾機[hatsujou] spring (e.g. coil, leaf)
ヒグス機構[higusukikou] Higgs mechanism (physics)
プロペラ機[puroperaki] propeller-driven aircraft
圧延機[atsuenki] rolling machine

お生憎様[oainikusama] that's too bad (ironical)
御誕生日おめでとうございます[otanjoubiomedetougozaimasu] Happy Birthday
隣の芝生は青い[tonarinoshibafuhaaoi] the grass is always greener on the other side
生きがいい[ikigaii] fresh (e.g. fish)
コンピューター援用生産[konpyuutaaenyouseisan] computer-aided manufacture

委託生[itakusei] scholarship student sent by government office or business
生す[nasu] to build up
異常発生[ijouhassei] plague
医学生[igakusei] medical student
医学生物学[igakuseibutsugaku] medical biology

一系[ikkei] single-family lineage
家系[kakei] family lineage
革新系[kakushinkei] liberal
共産系[kyousankei] communist controlled
銀行系カード[ginkoukeikaado] bank issued credit card

系図[keizu] family tree
系図学[keizugaku] genealogy (the study)
系統[keitou] system
系統樹[keitouju] genealogical tree

アルファ線[arufasen] alpha rays
エックス線[ekkususen] X-ray
サイン曲線[sainkyokusen] sinusoid
スピード線[supiidosen] speed lines
緯線[isen] parallel

一次線輪[ichijisenrin] primary coil
一線[issen] line
一直線[icchokusen] straight line
一番線[ichibansen] track no. 1
一塁線[ichiruisen] first-base line