Of the nature of or constituting a canon or rule; accepted as a norm or rule: as, canonical writings.Forming a part of the sacred canon. See canon, 3.Conformed or conforming to rule; fixed or determined by rule; specifically, regulated by or in accordance with the canons of the church; authorized: as, canonical age; canonical hours.[Cf. ML. canonicæ vestes, canonicals.] The dress or habit prescribed by canon to be worn by the clergy when they officiate; hence, the prescribed official costume or decoration of any functionary, as, in English usage, the pouch on the gown of an M.D., the coif of a serjeant-at-law, the lambskin on the hood of a B. A., the strings of an Oxford undergraduate, the tippet on a barrister's gown, proctors' and subproctors' tippets, etc.