Final answer:
P.S.I.S.A. stands for Private security and investigative services act. It refers to legislation that regulates and sets standards for private security companies and investigators.
Step-by-step explanation:
P.S.I.S.A. stands for Private security and investigative services act. This term refers to legislation that governs the regulation and standards for private security companies and investigators. It outlines the rules and guidelines that these entities must follow to ensure the safety and security of individuals and organizations. This act regulates the private security industry and dictates the standards for individuals and companies providing private security services, including the requirements for training, conduct, and licensing of security professionals such as guards and private investigators.