ちょっと一杯[chottoippai] let's have a quick drink
ばつ一[batsuichi] being once divorced
一向[hitaburu] nothing but
サラダ一皿[saradahitosara] plate of salad

安全第一[anzendaiichi] safety first
一か八か[ichikabachika] sink or swim
一っ走り[hitoppashiri] spin (as in 'take a car for a spin')
一つ一つ[hitotsuhitotsu] one-by-one

グリーン車[guriinsha] green car (1st class)
愛車[aisha] (one's) beloved car
医療車[iryousha] clinic car
井戸車[idoguruma] well pulley
１等車[ittousha] first-class carriage (coach)

一輪車[ichirinsha] unicycle
横車[yokoguruma] perverseness
下り列車[kudariressha] trains going away from the capital
下車[gesha] alighting (from train, bus, etc.)
火の車[hinokuruma] fiery chariot (which carries the souls of sinners into hell)

ダイヤの指輪[daiyanoyubiwa] diamond ring
一次線輪[ichijisenrin] primary coil
一輪[ichirin] one flower
一輪車[ichirinsha] unicycle
花輪[hanawa] wreath

競輪[keirin] keirin
金輪際[konrinzai] the deepest bottom of the earth
九輪[kurin] kurin (nine vertically stacked rings of a pagoda finial)
結婚指輪[kekkonyubiwa] wedding ring
月の輪[tsukinowa] moon (esp. full moon)