That's why we call ourselves back-end/front-end/ui/embedded (software) engineers.
For instance, the product I work on daily has no UI (ok, it has a 2 page UI used by an ops group) - is that "back end" when there's no "front end"?
And apologies - this is a bit OT here and I'm not trying to be difficult nor argumentative, I've just often wondered if the majority of people view backend/frontend as specialized terms like I do or if it's really just a generic term for "works on visualization/UI" and "works on the other stuff"