Someone posted the following question on Stack Overflow. It didn't fit there and got deleted, but this seems like a good place to repost it. Here is the question, slightly edited by me:
I am studying computer science and notice that the field includes a lot of engineering discipline.
Can computer scientists call themselves engineers too?
They often do call themselves that.
Moreover, it was possible in the U.S. to earn a professional engineer's (P.E.) license in software engineering, though NCEES seems to be discontinuing that.
Among programmers, at any rate in the United States and perhaps in some other countries, it is normal to refer to software engineers as engineers. The general public too understands the term "software engineer." On the other hand, if a P.E. specializing in, say, electric power engineered a building's plumbing and ventilation, that might be plausible, whereas if a software engineer engineered that, a lawsuit would presumably ensue. So, mostly the answer is yes but it depends on the context.
I mention the electric power engineer as an example because I happen to be one of those, and at the age of 51 I have been around a bit. I can tell you that, 30 years ago, the name "software engineer" was perceived as a bit pretentious. However, software engineers have been busy since then. They have advanced their field tremendously. They also now use many standard engineering methodologies. They have other methodologies of their own.
Consider for example the software-engineering methodology of test-driven development, a methodology that brings a sharp engineering focus on deliverable quality metrics. If that is not an engineering methodology as such, it is hard to say what else it might be. Moreover, like other engineers, software engineers today apply graduate-level mathematics to model, analyze and transform engineering problems. For these reasons and others, today, electrical engineers, mechanical engineers, civil engineers tend to accept software engineers more or less as one of their own—or if not wholly as one of their own, precisely, then at least as allied professionals worthy of a serious level of technical respect.
In short, the answer is mostly yes, at least in some countries like the U.S. and the U.K. (As @PhilipKendall observes, however, in other countries, perhaps most notably Canada, the answer is very definitely "no".)