Name of hat covering teacher's head (5)
I believe the answer is:
title
'name' is the definition.
(eg the name of a book)
'hat covering teacher's head' is the wordplay.
'hat' becomes 'tile' (old-fashioned term for a hat).
'covering' indicates putting letters inside.
'head' suggests taking the first letters.
The initial letter of 'teachers' is 't'.
'tile' enclosing 't' is 'TITLE'.
'of' acts as a link.
(Other definitions for title that I've seen before include "big role" , "Document showing legal right to possess a property" , "What could be professor's" , "confers ownership" , "Right - name - address" .)