Same Origin Policy
In plain terms
A browser rule restricting cross-site resource access.
Going deeper
The same-origin policy prevents a page from reading data from a different origin (scheme, host, port), a core web security boundary. It isolates sites from each other.
Under the hood
CORS selectively relaxes it for trusted cross-origin requests; foundational to web security.
Examples
Browser security, CORS, cross-origin restrictions, XSS/CSRF defense.
Think of it like...
Like a rule that you can't reach into a neighbor's house just because you're next door.