acceleration acceleration /əkˌsɛləˈreɪʃən/

noun

1. () The act of accelerating; increasing the speed  ( quickening , speedup , acceleration )
   the act of accelerating; increasing the speed
   
2. () An increase in the rate of change  ( acceleration )
   An increase in the rate of change
    Modern science caused an acceleration of cultural change
   modern science caused an acceleration of cultural change
   
3. () (physics) a rate of increase of velocity  ( acceleration )
   (physics) a rate of increase of velocity