On-hook Definition

Describing the state of a telephone (similar device) when it is available but not in use.

(by extension) Describing the idle state of a subscriber or PBX user loop.

A condition that exists when a telephone receiver or handset is in its cradle and available to receive an incoming call. The term refers to the fact that early telephone handsets hung from a switch hook, a hook that activated a switch. See also off-hook.