1
general::
Suspend or dismiss from a university, principally a British one. For example, He's done very poorly ever since he was sent down from Oxford. [Mid-1800s]
American Heritage Idioms
2
general::
Phrase(s): send someone or something down
to dispatch someone or something to some place on a lower level. • They wanted someone downstairs to help with the moving, so I sent John down. • I sent down John to help.
McGrawhill's American Idioms And Phrasal Verbs