rev, n. & v. colloq.
--n. (in pl.) the number of revolutions of an engine per minute (running at 3,000 revs).
--v. (revved, revving)
1 intr. (of an engine) revolve; turn over.
2 tr. (also absol.; often foll. by up) cause (an engine) to run quickly.
rev counter = revolution counter.