transitive verb
1. to cause (a particular activity or process) to happen faster.
He accelerated his college program and received his degree early.
2. to increase the speed or rate of.
He noisily accelerated his motorcycle as he drove past his friends.
intransitive verb
1. to increase the speed or rate of something.
She accelerated quickly in order to pass the car safely.
2. to change speeds from a slower rate to a faster rate.
Be careful on the highway, because this car accelerates slowly.