Lewis & Short

Măcrŏbĭus, ii, m., = Μακρόβιος (living long): Aurelius Macrobius Ambrosius Theodosius, a Roman grammarian at the end of the fourth century, author of a commentary on Cicero’s Somnium Scipionis, and of a treatise entitled Convivia Saturna lia, cf. Jan. Proleg. ad Macr. p. 1 sq.