:tenured graduate student: n. One who has been in graduate school
for 10 years (the usual maximum is 5 or 6): a `ten-yeared'
student (get it?). Actually, this term may be used of any grad
student beginning in his seventh year. Students don't really get
tenure, of course, the way professors do, but a tenth-year graduate
student has probably been around the university longer than any
untenured professor.
-- The AI Hackers Dictionary