- deceleration; reducing speed; a slowdown
減速する slow down; decelerate; reduce one's speed
- 車を時速40キロに減速する
- reduce [decrease] the speed of a car to 40 kilometers an hour/bring [slow] a car down to 40 kilometers an hour
- 減速経済decelerated economy; a slowdown in economic activities
- 減速材[剤]a moderator
- 減速装置[歯車]a reduction gear