/rev/ , n. , v. , revved, revving . Informal.
n.
1. a revolution (in an engine or the like).
v.t.
2. to accelerate sharply the speed of (an engine or the like) (often fol. by up ).
v.i.
3. (of an engine) to accelerate; become revved (often fol. by up ).
4. rev up , to increase in strength or accelerate sharply: The economy is beginning to rev up.
[ 1900-05; short for REVOLUTION ]