cre·do 
(kr
ēd
ō, kr
ā-)
n. pl. cre·dos 1. A creed.
2. Credoa. The Apostles' Creed.
b. The Nicene Creed, especially as the third item of the Ordinary of the Roman Catholic Mass.
c. The musical setting of the Nicene Creed.
[Middle English, the Apostles' Creed, from Latin crēdō, I believe (the first word of the Apostles' Creed or the Nicene Creed), first person sing. present tense of crēdere, to believe; see kerd- in the Appendix of Indo-European roots.]