Lewis & Short

ĕpistŭlāris (epistol-, v. epistula init.), e, adj. [epistula], of or belonging to a letter, epistolary.

  1. I. Adj.: chartae, letter-paper, Mart. 14, 11 in lemm.; Dig. 33, 9, 3, § 10: colloquium, epistolary, Aug. Ep. ad Marcell. 5.
  2. II. Subst.: epistŭlāris, is, f., a messenger of the Eagle of Jupiter: epistularis tua, Mart. Cap. 9, § 896.
    Plur.: epistulāres, ium, m., state secretaries, Cod. Th. 6, 30, 7.