What's a pull request in GitHub?

Related questions

1. What is git push request?
2. What is a GitHub commit?
3. What is git flow?
4. How do I add a branch to my github repository?
5. Do you need git to use GitHub?
6. Why is it called pull request?
7. How do I check in git?
8. What is the use of branch in git?
9. How do I retrieve a git repository?
10. What is Gitflow workflow?

Tags

1. #commits
2. #changes
3. #review
4. #potential
5. #request
6. #requests
7. #before
8. #others
9. #discuss
10. #branch
11. #follow
12. #repository
13. #pushed
14. #merged
15. #github
16. #collaborators
17. #about
18. #opened