grimoire.

Borrowed from French grimoire, a variant of grammaire, from Old French gramaire (“grammar; grimoire; conjurer, magician”), from Latin grammatica (“grammar; philology”), from grammaticus (“relating to grammar, grammatical”), from Ancient Greek γρᾰμμᾰτῐκός (grămmătĭkós, “knowing one's letters; concerned with textual criticism”), from γράμμα (grámma, “that which is drawn or written; letter; book, writing”) + -ῐκός (-ĭkós, suffix added to noun stems to form adjectives). γράμμα is derived from γρᾰ́φω (grắphō, “to cut into, scratch; to draw, paint; to write”, ultimately from Proto-Indo-European *gerbʰ- (“to carve”)) + -μᾰ (-mă, suffix added to verbal stems forming neuter nouns denoting the result of, a particular instance of, or the object of an action). The English word is a doublet of glamour, glamoury, gramarye, and grammar.