Meaning of ACCELERATION in English

ac ‧ cel ‧ e ‧ ra ‧ tion /əkˌseləˈreɪʃ ə n/ BrE AmE noun

1 . [singular, uncountable] a process in which something happens more and more quickly

acceleration in

an acceleration in the rate of inflation

acceleration of

the rapid acceleration of economic progress in South East Asia

2 . [uncountable] the rate at which a car or other vehicle can go faster:

The latest model has excellent acceleration.

3 . [uncountable] technical the rate at which the speed of an object increases

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.