I know the two terms get thrown around a lot, and within software development it doesn't seem to matter who is an 'engineer' or not, but in most other disciplines the word 'engineer' has a special connotation, like how 'doctor' means something specific in the medical world.
For me the traits of an 'engineer' that stand out from other workers in their field:
So how does this apply to software development? I think the term engineer communicates these ideas:
Hopefully that gives a little insight into how people hear the term 'engineer' and what they expect it to mean in all other industries. I think it's only our industry (with so many self-taught leaders) where the term gets muddied and devalued.