Source control can easily be identified if it is split down. The source is the group of files that are part of the project that the person is working on. Second is control which is obviously the act of making changes to these files in whatever way the person desire.
One of the most popular software that uses source control is GitHub. In the software, the person can upload the files that they are currently working on. Github then saves this as the first version in the project. Then another person can download these files and make their changes. When they go to reupload them GitHub will save this as another version of the project. That way if someone within the group of people that are working on it makes a mistake, they can go back to a previous version. One feature of GitHub which are good is that when someone has downloaded the files it means that the other people can not download them. The reason it does this is so that more than one person are not working on the same version and making changes which ignore the changes the other person has modified.