— Creed, adopted for liturgies in 325 (6)
I believe the answer is:
nicene
(Other definitions for nicene that I've seen before include "Creed of Christian belief adopted in 4th century" , "This Creed is a formal statement of Christian belief from 4th century" , "The - Creed is used in Christian liturgies" , "Christian Creed adopted in 325 a.d." , "The -- Creed, a Christian profession of faith" .)