Rare word #12: heortology

I'm bringing back the occasional posting of rare or interesting words. I've also decided to start labeling some topics for easier browsing (e.g. interviews, rare words, books). You can imagine how difficult it will be to categorize posts after the fact, so please bear with me as slowly comb through posts.

heortology: (noun) [From the Greek ἑορτή "festival" and λόγος "knowledge, discourse"] Etymologically implies a relation to feasts or festivals in general, an exposition of their meaning.

The word, however, is used to denote specifically the science of sacred festivals, embracing the principles of their origin, significance, and historical development, with reference to epochs or incidents in the Christian year.