> Tools such as GitHub and Bitbucket choose the name pull request since the first manual action would be to pull the feature branch. Tools such as GitLab and Gitorious choose the name merge request since that is the final action that is requested of the assignee
I think GitLab are right to choose 'merge request', it has an immediately obvious meaning compared to 'pull request'
Gitlab's terminology is actually closer to the underlying VCS terminology.
git pull <branchname> // fetch <branchname> from a remote host AND merge it into the current branch.
git merge <branchname> // merge <branchname> into the current branch
I suspect it's someone's pet peeve that "Pull Requests" are named incorrectly and they got an opportunity to rename them when building Gitlab.