Hello to the old Romans (3)
I believe the answer is:
ave
'hello to the old romans' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ave that I've seen before include "Hail as to Maria" , "Hail as to Caesar" , "Hail in old Rome" , "Hail (Latin)" , "Hail in graveyard." .)