n. A diesel engine.n. A vehicle powered by a diesel engine.n. The type of gasoline designed to power a diesel engine.verb-intransitive. To continue running after the ignition has been turned off, as when an open throttle supplies fuel to an engine that is still sufficiently hot to ignite it.verb-intransitive. To drive a diesel-powered vehicle: We dieseled through the countryside. verb-intransitive. To refuel a diesel-powered vehicle. Often used with up.