(mahjong) Alternative spelling of 一萬 (“the tile of 1 wan”)

repetitive, one-track

the same behavior repeated over and over again / being in a rut / (of a person) having a one-track mind

number one

(poker) Synonym of ペア (pea, “pair”); a one pair

The act of calling someone and then immediately hanging up, in the hope that the recipient of the call will call back.

one hand

(metaphorical) cushion to soften a blow or impact

(baseball) one-hopper

(baseball, of a ball) to bounce once