This is the speed of the engine with the following conditions: the transmission is in neutral (or park in automatic transmissions ), the engine is fully warmed up, the choke butterfly is fully open, and there is no extra accessories in operation (i.e., air conditioner , radio, lights).
IDLE SPEED
Meaning of IDLE SPEED in English
English dictionary of automotive terms. Английский словарь автомобильных терминов. 2012