What is idle?

idle air-control valve

Glossary “idle air-control valve” Definition:
An electrically operated valve that, on commands from the engine-control computer, varies the size of an air passage that bypasses the throttle plate of an electronic fuel-injection system, thus controlling idle speed.

idle

Glossary “idle” Definition:
The engine speed with no load and the accelerator pedal fully released. An engine operating mode during which only enough power is required and produced to keep the engine running and to carry loads applied by the transmission and accessories. Idle is a very low engine speed.