My advice is to stay away from "FOSS" unless you're GPL, and "open source" unless you're an OSI-certified license. It's not that I don't think those terms apply

My advice is to stay away from "FOSS" unless you're GPL, and "open source" unless you're an OSI-certified license. It's not that I don't think those terms apply to anything other than that, but using those terms invites debate about licensing and attempts to control language instead of discussion of your project. "Source available" is a term that usually no one gets mad at.