You are about the open source part: http://opensource.org/osd. The 'Naming' section of your link references the osd.

Calling it just one or the other is enough though. Being "under a Free Software license" by definition means "the code is open (i.e. you can study it), so no need to say "and Open Source".

I do however prefer calling it free software over open source as I find the free software definition simpler and than the osd. And also because the term open source seems to place importance on the code being 'open' instead of 'libre', which you'll here rms talking about everytime someone says open source.

"Free software" has issues as well as a term, since free can obviously mean two things, gratis or libre. However, once the reader/listener has understood the difference between free of charge software and software that preserves your freedom to study, modify and redistribute it, I think open source is the more problematic term as it can more easily cause confusion as demonstrated by your comment (where you think open source means that the code just has to be 'open').