decelerations

/D IH0 S EH0 L ER0 EY1 SH AH0 N Z/
noun
  1. 1

    The act or process of decelerating.

    โ€œThe rocket is now in deceleration.โ€

  2. 2

    The amount by which a speed or velocity decreases (and so a scalar quantity or a vector quantity).

    โ€œThe brakes produce a deceleration of 10 metres per second.โ€

Antonyms

Source: https://en.wiktionary.org/wiki/deceleration, https://en.wiktionary.org/wiki/decelerations