surveillance
Careful watching of people or places, usually for safety.
Surveillance is the close observation of people, places, or activities, usually to gather information or monitor what's happening. When a store uses security cameras to watch for shoplifters, that's surveillance. When parents check a baby monitor to see if their infant is sleeping safely, that's surveillance too.
Police might conduct surveillance of a suspect's house to see who comes and goes. Wildlife biologists use camera surveillance to study how animals behave when humans aren't around. Schools might use surveillance cameras in hallways to help keep students safe and prevent problems.
Surveillance can serve important purposes: catching criminals, protecting property, or ensuring safety. But it also raises questions about privacy. Being watched constantly can feel uncomfortable, even if you're not doing anything wrong. A student might feel differently about surveillance cameras in school hallways versus cameras in a bathroom, where the need for privacy is obvious and important.
The person or group doing the watching matters too. Government surveillance of its citizens requires careful thought about balancing security with freedom. Democratic societies often debate how much surveillance is appropriate and what limits should exist to protect people's privacy and liberty.