A person who supervises students as they take an examination, in the United States at the college/university level; often the department secretary, or a fellow/graduate student; an invigilator.
"The graduate proctor reminded us to stop talking and begin writing our answers immediately."
watch over (students taking an exam, to prevent cheating)
"The teacher sat quietly at the back of the room as a proctor to ensure no students looked at their neighbors' papers during the final."
to function as a proctor
"The university hired three students to act as proctors during the final exams to ensure no cheating occurred."
Pertaining to the Proctor test, a standardized test measuring soil moisture-density, especially for the requirements of construction projects.
"The civil engineer failed the proctor test because the soil samples did not meet the required density specifications for the new highway foundation."
A surname, from occupations​.
"The genealogy club discovered that our new neighbor's last name, Proctor, originated from his great-great-grandfather's job as an exam supervisor."
The word comes from Middle English procatour, a shortened form of procuratour. Its original meaning relates to acting on behalf of another person.