say it: ak-sel-ur-AY-shuhn
acceleration is a noun meaning "an increase in rate of change". It carries 3 recorded senses.
an increase in rate of change
“modern science caused an acceleration of cultural change”
the act of accelerating; increasing the speed
(physics) a rate of increase of velocity
physics
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for acceleration come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.