Cross-Origin Resource Sharing (CORS): A mechanism that allows restricted resources on a web page, served from a different origin (domain, protocol, or port), to be requested from another domain outside the domain from which the resource originated.
Analogy: Imagine a gatekeeper controlling access to a building. CORS is like a set of rules that the gatekeeper uses to decide who can enter from which other buildings.
Why It Matters: It is crucial for enabling secure communication between different domains in web applications, especially when using APIs.