A pull request (PR) is a request, opened on a Git hosting platform, to merge one branch's changes into another — bundling a diff, a discussion thread, and any automated checks into a single reviewable unit before the merge happens.
A pull request isn't a feature of Git itself — it's a collaboration layer that hosting platforms like 📝GitHub and GitLab add on top of Git's branching and merging primitives. An author pushes commits to a branch, then opens a PR proposing to merge that branch into a target branch, often a shared branch like main or staging. From there, the platform can run automated checks (tests, linters, security scans), collect reviewer comments and approvals, and — if 📝branch protection rules are configured — refuse to allow the merge until those checks and approvals pass.
Once satisfied, the PR merges, folding its commits into the target branch, and typically closes automatically. A PR that's abandoned instead of merged can simply be closed without affecting the target branch at all.