A while back, I was talking with another student and she stopped me in mid-blabbing to ask, "What's a prof?"
It turns out that she had never heard anyone say "prof" (short for "professor") before until me. Is that weird or what? I thought everyone knew about the abbreviated word "prof".
Of course, I never address a professor as "Prof"--I always call him/her "Professor (insert last name here)" or "Doctor (insert last name here)" or even "(insert first name here)" if we're on a familiar basis.