When we make projects, we need a directory can hold every documents. Git has versions of directories such as directory_ver1.0, directory_ver1.5, directory_ver1.8, .... Now we can call all directories "Repository". Actually repository doesn't mean all of the directories. There is hided ".git" directory inside of repository which has CHANGEs of project.
During making projects, you might want to save "this version of repository". Then you can "COMMIT" that version of project directory. We can control versions of directory with this function.
