Software: Free? Open source?

When we talk about software, there are terms like "free", "open source" etc.

What do these terms stand for?

Free software: "Free" stands for freedom. Free software stands for the possibility for users to run, study, change, redistribute, modify the software. Official Definition. So this term does not tell you anything about the monetary price of the software.

Open source software: "Open" stands for open access to source code. If you think about free software's possibility to modify the software, free software practically always needs to be open source, but open source software does not have to be free software. Official Definition