Church hymn
'church hymn' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for te deum that I've seen before include "Ancient liturgical hymn" , "music" , "Ancient Christian hymn" , "Christian hymn of thanksgiving" , "Canticle" .)
'church hymn' is the definition.
(I've seen this before)
This is the entire clue.