Definition of mortier in English:

mortier

Pronunciation /ˈmɔːtɪeɪ/

noun

rare
  • In France: a cap worn by various officials as an emblem of high office.

    The mortier was formerly worn by the Chancellor of France and the Presidents of the French parliaments and is now worn, in a modified form, by senior officials and magistrates of the Cour des Comptes (the National Audit Office) and the Cour de Cassation (the Supreme Court of Appeal).

Origin

Early 18th century; earliest use found in Ephraim Chambers (?1680–1740), encyclopaedist. From French mortier.