deceleration

noun
1
a reduction in the speed at which a vehicle is travelling
کاهش سرعت, کم شدن سرعت, کند شدن
2
the act or process of slowing down; the act or process of making something slower
کاهش سرعت, کند شدن, آهسته سازی, آهسته کردن
a deceleration in economic growth