Are “Open Source” and “Free Software” the same thing?
Yes and no. Technically, the great majority of open source programs are free software and vice-versa. In terms of philosophy, things are quite different. The term “open source” was coined to make “free software” more attractive, its supporters see open source software as a better way to make software. Supporters of the “free software” term value the freedom, not merely the way software is made, and thus argue that the term “open source” misses the point. Which term you employ simply depends on your vision of software.