Praver’s verse, a line ignored by eg Brunnhilde (5)

I believe the answer is:

kyrie

I'm afraid I can't explain this answer.

(Other definitions for kyrie that I've seen before include "First section of Mass" , "Greek prayer" , "- - eleison" , "Part of the Mass" , "First word of Latin Mass" .)

I've seen this clue in The Times.

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