Cross-Origin Resource Sharing - mechanism that allows web pages to access resources from other domains. Like having permission slips that allow websites to share resources safely.
Web applications configure CORS to allow their frontend to communicate with APIs hosted on different domains.
CORS is a web security standard implemented by browsers and configured via HTTP response headers on your web server, API gateway, CDN, or storage origin. Cloud providers don’t have a single “CORS service,” but many services let you set CORS rules (allowed origins, methods, headers) for APIs, storage buckets, and CDN/origin responses.