Yes, that seems to be sort of what they are. Here's a definition:
A natural oil typically obtained by distillation and having the characteristic fragrance of the plant or other source from which it is extracted.
That doesn't really mean they're "good", though. I suppose you could distill an "essential oil" from poison ivy.
However, don't lump "fragrance free" in with all this. While I suppose some people are, or at least believe themselves to be, allergic to perfume, there're other reasons to make products scentless. Most women use actual perfume at least sometimes. They don't want their deodorant to compete with it.