is a fairly uncommon word. It's not very nice to use such a difficult word to explain the meaning of an easy word... Anyway, here its meaning is more of "ritual/ceremony _**and**_ music" rather than "ritual music". So it's one of the compounds that just mean "A and B", such as , , , , and . Music played by a doesn't have to be ritual music or religious music. For example, it's perfectly fine to hold a rock concert at .
According to dictionaries, refers to the two elements traditionally considered important by Confucianists. It's rarely used outside the context of Chinese history. Here is not just etiquette but a broader concept that includes manners, ritual, courtesy, respect, etc. Dictionaries say can refer to human culture itself by extension.