A security guard is a person employed by a private party to protect the employing party’s assets (property, people, equipment, money, etc.) from a variety of hazards (such as waste, damaged property, unsafe worker behaviour, criminal activity such as theft, etc.) by enforcing preventative measures.
Security guards do this by maintaining a high-visibility presence to deter illegal and inappropriate actions, looking (either directly, through patrols, or indirectly, by monitoring alarm systems or video surveillance cameras) for signs of crime or other hazards (such as a fire), taking action to minimize damage (such as warning and escorting trespassers off property), and reporting any incidents to their clients
Security officers are generally uniformed to represent their lawful authority to protect private property.
Security guards are generally governed by legal regulations, which set out the requirements for eligibility (e.g., a criminal record check) and the permitted authorities of a security guard in a given jurisdiction. The authorities permitted to security guards vary by country and subnational jurisdiction.