idiot light

1. 1.

   a colored warning light on an instrument panel (as for low oil pressure)

   Broaderred light

   Part ofcontrol panel

Questions about idiot light

What does idiot light mean?

idiot light means "a colored warning light on an instrument panel (as for low oil pressure)".

Is idiot light a common word?

idiot light is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.