ianae, but the dictionary provides plenty of examples of how you can be one without having an actual degree to that effect.
For example, someone 'engineers' something if it is built according to scientific principles. The person doing so is therefore, by definition, an engineer.
However, protected job titles, such as Engineer, should be protected and venerated, because the persons achieving that status are likely to have to much broader set of skills than someone who just 'engineers' stuff in their garage (nothing wrong with that mind).
For example, I design secure networks for large corporations. It requires a large number of skills to accomplish (not just technical), but I'm not an Architect, I'm an architect. I still get paid :)