caller

Caller is a term used to designate the person, device, or context that initiates a call or request. In telecommunications and voice networks, the caller is the party who originates a telephone call or other voice connection; the recipient is the callee or called party. Modern systems commonly provide caller ID, which transmits information about the caller to the callee’s device. The term calling party is also used in some contexts, while in certain regions marketing or automated announcements refer to the initiator as the caller.

In computing and software, caller describes the code or function that invokes another routine. When function A calls function B, A is the caller and B is the callee. This relationship is central to the call stack, which records the sequence of active calls. Debugging, profiling, and error reporting often reference the caller to trace how execution reached a given point. Some programming languages offer a caller attribute or a way to inspect the caller, while others restrict or deprecate such access for security or performance reasons.

Across domains, the core notion is that the caller is the initiator of an action, whether a voice connection, a software function invocation, or an API request. The exact meaning depends on context, but the term remains common in both human communication and computer science.