A github fork is a personal copy of a repository. From the docs, a github fork "allows you to freely experiment with changes without affecting the original project." The command "git clone" allows you to clone a repo somewhere else. However, GitHub conveniently keeps track of the changes between both versions of the repo allowing you to directly visualize changes between them. Forks are connected to the original project and allow you to "contribute back to the original project using Pull Requests." Cloning, however, is more isolated and intended for quick copying of a repo. Furthermore, you "won't be able to contribute back to it [main repo] unless you are specifically invited as a collaborator." The "git branch" command allows you to view, create and delete branches. Branches are diverging versions of the main repo where people are free to modify and add files without breaking the original project. Furthermore, you can merge back to the "master" (AKA main) branch once it has served it's purpose. The main difference between branches and forks is that branches are intended to be "short-lived" and possibly combined with the main branch after development, whereas forks are often used when one wishes to split from the main project while inheriting the current repo. The point here is that the forked repo will likely not rejoin the master.