English to English

noun (n)

• a decrease in rate of change(noun.attribute)

  Example:
  The deceleration of the arms race.
  

  Synonym:
  retardation, slowing
  Antonym:
  acceleration
  

  source: wordnet30
• (physics) a rate of decrease in velocity(noun.time)

  source: wordnet30
• the act of decelerating; decreasing the speed(noun.act)

  Example:
  He initiated deceleration by braking.
  

  Antonym:
  acceleration, quickening, speedup
  

  source: wordnet30