credo

Etymology

Inherited from Middle English credo, from Old French credo, from Latin crēdō (“I believe”); doublet of creed.

noun

1. A statement of a belief or a summary statement of a whole belief system; also (metonymically) the belief or belief system itself.
   credo quia absurdum
   “You’re either with me or you’re against me” became Dany’s credo, and those against her were an ever-changing multitude to be determined solely by her whims. 19 May 2019, Alex McLevy, “The final Game Of Thrones brings a pensive but simple meditation about stories (newbies)”, in The A.V. Club
2. (Christianity) The liturgical creed (usually the Nicene Creed), or a musical arrangement of it for use in church services.
   Credo III is so beautiful!
   Until the mid-1970s, however, most Catholic hymnals contained at least one musical setting of the creed […] By the 1980s hymnals having sung credos were mainly those devoted to "traditional" styles of church music […] 1996, Pastoral Music, volume 21, page 12