Christmas trio (4)
I believe the answer is:
magi
'christmas trio' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for magi that I've seen before include "Wise men, visitors to Bethlehem" , "Wise men who were guided by a star" , "The three Wise Men of Bethlehem" , "Persian wise men" , "Caspar, Melchior and Balthasar" .)