What term represents the act of identifying and alerting to the presence of an intruder?

The term that represents the act of identifying and alerting to the presence of an intruder is "detect." Detection involves recognizing and confirming the presence of unauthorized individuals, which is a critical first step in responding to potential security breaches. Effective detection systems can include alarms, surveillance technologies, or physical security personnel who monitor for unusual activity.

In this context, the emphasis is on being aware of an intruder's presence, which allows for timely responses such as alerting security forces or activating additional security measures. The successful identification of threats enhances overall security and safety protocols within any environment.