Yeah the term engineer is thrown around pretty casually in the software world. You can apprentice and take the PE (Professional Engineer) test, but it's often hard to find software engineers with their PE certificate. It's much more common in other fields like Mechanical, Electrical, and primarily Civil.

It all my years (15) of professional experience, I've only worked under one PE, an Electrical Engineer.

In some states you literally can not have "engineer" in your job title unless you have a PE certificate/accreditation/whatever.