I think you should include it prominently in the design, but also make it a point to answer that question, either via the first question in a FAQ, or somewhere else that's very clear.
For example on "Bob's Royalty-Free Widgets", I would see Royalty-Free as part of the logo/header, and then perhaps on the homepage, in the copy, the bolded question "What's Royalty-Free? " and then underneath, "Glad you asked! Royalty-free means blah blah blah [read more]"
That way you're pushing it as a selling point to the folks who already know what it is, but also making the advantage very clear for those that don't.
In general, I think most designers and developers have a pretty good idea of what royalty-free means. Devs are used to licensing concepts because they code they learn from, publish, and contribute to is generally under some license or another.
Some of how you handle the visual presentation depends on how you want the public perception of your company to feel. If you over-explain what royalty-free means, more experienced people may feel your primary customers are amateurs if have to go out of your way to explain it so much. So consider that when you make your decision, and try to find a solid balance. If you're trying to seem a little more upper-crust, include "royalty-free" in your logo/header (and for SEO, your title), and just make your FAQ clearly accessible. On the product pages themselves, you can re-emphasize royalty-free and what that means as well.