canonical (adj.)

early 15c., "according to ecclesiastical law," from Medieval Latin canonicalis, from Late Latin canonicus "according to rule," in Church Latin, "pertaining to the canon" (see canon (n.1)). Earlier was canonial (early 13c.). General sense of "conformed or conforming to rule" is from 1560s. Meaning "of or belonging to the canon of Scripture" is from 1560s; hence "of admitted excellence" (1550s).