The Collaborative International Dictionary of English v.0.48:

Montem \Mon"tem\, n. [L. ad montem to the hillock. See Mount,
   n.]
   A custom, formerly practiced by the scholars at Eton school,
   England, of going every third year, on Whittuesday, to a
   hillock near the Bath road, and exacting money from all
   passers-by, to support at the university the senior scholar
   of the school.
   [1913 Webster]