Crescent crescendo

While at band practice yesterday, executing a lovely crescendo, it suddenly occurred to me that the word “crescendo” is probably related to the word “crescent”. Crescendo= sound that is building or getting louder, crescent = the shape of the moon while it’s getting fuller. Sure enough, there’s a Latin word cresco, crescere, crevi, cretum meaning to grow or swell, present participle crescens, crescentis. But what about a moon that’s going from a half moon to a new moon? It’s still crescent in shape, but it’s not growing, it’s shrinking. My dictionary has the word decrescent as an adjective, meaning waning, but not as a noun. And if memory serves, the moon waxes on the right and wanes on the left, but usually when you see a crescent (such as on the Turkish flag) it’s on the left, meaning it’s really a decrescent, or would be if that were a word. Maybe the delightful flaky French roll should really be called a “decroissant”.