An acronym for "Check Engine Light"
The Check Engine light is an indicator lamp placed on the vehicle's dashboard. Typically amber or red coloured, this malfunction indicator lamp (MIL) indicates a problem with the computerized engine management system. It often has an icon in the shape on an engine.
Note that if it is flashing on and off this means that misfire that will damage the catalytic converter is in progress. In this case the engine should be turned and repaired before being returned to service.