The way Google uses it, a "CL" means both "a thing you sent out for pre-commit review" and "a submitted change". It's very similar to a GitHub PR, if you use a master branch and always squash your PRs when merging to master.
CL: Stands for “changelist,” which means one self-contained change that has been submitted to version control or which is undergoing code review. Other organizations often call this a “change” or a “patch.”