Mathematicians have largely abandoned the term "imaginary number" and use "complex number" instead. I never used the term "imaginary number" when I was teaching

Mathematicians have largely abandoned the term "imaginary number" and use "complex number" instead. I never used the term "imaginary number" when I was teaching (except to point out that it wasn't very good terminology). But the old term still survives in some areas. For instance, the real and imaginary parts of a complex number: re (3 + 4 i) = 3 and im (3 + 4 i) = 4.