In cybersecurity and networking, a 'peer' refers to a computer, device, or user that has equal privileges and responsibilities within a network. Unlike traditional client-server models, where one device provides resources and others consume them, peers can both provide and access resources directly to and from each other. Peer-to-peer (P2P) systems enable decentralized sharing of files, data, or services, often improving efficiency and resilience but also introducing unique security considerations.