Source : WordNet®

rev
     n : rate of revolution of a motor; "the engine was doing 6000
         revs" [syn: {revolutions per minute}, {rpm}]
     [also: {revving}, {revved}]

rev
     v : increase the number of rotations per minute; "rev up an
         engine" [syn: {rev up}]
     [also: {revving}, {revved}]

revving
     See {rev}