[Git] A batch of changes to a repository, with a commit message.
[Phabricator] A batch of changes to a repository, after being landed (a.k.a. in “post-commit” stage).
[Phabricator] A single update to a Revision. Colloqually, a synonym for a Revision.
[Phabricator] When a Revision is landed, it is committed to the repository, and the Revision is marked as “closed”.
[Phabricator] A batch of Git Commits, before being landed (a.k.a. in “pre-commit” stage. Internally, a Git patch. A Revision is also tied to a single Git branch. Analogous to a GitHub “Pull Request”. See also, Diff.