It's a set of practices and an automated workflow in software development that aims to deliver software updates frequently, reliably, and efficiently. It's a core component of the DevOps methodology.
The entire automated process, from code commit to deployment, is often referred to as a CI/CD pipeline. This pipeline typically consists of several stages:
Source/Commit: Developer commits code to the repository.
Build: Code is compiled and packaged.
Test: Automated tests are run.
Deploy (to staging/testing): Application is deployed to a non-production environment.
Manual Approval (for Continuous Delivery): A human reviews and approves the release.
Deploy (to production): Application is released to end-users.