In the United States, the term "Professional Engineer" is a legal term describing persons licensed by their state. [1]
The generic title "engineer" is not legally protected and may be applied to software developers or many other professions where scientific understanding or invention is applied. For example, software developers at Amazon and Microsoft are called "Software Development Engineers".
Most electrical and computer engineering graduates do not bother with getting PE licensure; instead this is a requirement for civil, mechanical, aeronautical, and related engineering graduates.