Someone who is medically qualified and investigates deaths occurring under unusual or suspiciouscircumstances. Often this involves autopsies as well as some investigation similar to a forensics major.
"Didn't you hear? Mariah got her doctorate and became a medicalexaminer. Now she works in a morgue!"
Someone appointed from another institution by a university to question every little, trivial detail of an assessment or graded paper in order to justify their own hefty stipend, make lecturers' lives annoyingly miserable (thus reminding them they are still only employees) and to feign the appearance of academic quality.
Elvira: Leo the external examiner has returned your examination for review because some of the questions require commas to be added. Make sure you do this before you leave the office at 2.30pm today.
Chuck: If all Leo has to do for his money is correct my grammar, then I'd be grateful if you'd ask him to stick that examination paper up his fat arse.