Mater lead-in (4)
I believe the answer is:
alma
'mater lead-in' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for alma that I've seen before include "The . . . . Mater is the old school" , "Battle of the -- was in the Crimean War" , "One's university" , "Woman" , "Essence" .)