armillum, i, n. [acc. to Paul. ex Fest., from armus; v. infra], a vessel for wine (ante- and post-class.): armillum, quod est urceoli genus vinarii, Varr. ap. Non. p. 547, 15: armillum vas vinarium in sacris dictum, quod armo, id est humero deportetur, Paul. ex Fest. p. 2 Müll.
Hence the proverb, ad armillum revertere, or redire, or simply, ad armillum, to return to one’s old habits, to begin one’s old tricks again, Lucil. ap. Non. p. 74, 13: at illa ad armillum revertit et ad familiares feminarum artes accenditur, App. M. 9, p. 230, 22.
With a more pointed reference, Appuleius, speaking of Cupid, changes armillum in the proverb into armile = armamentarium, an armory, M. 6, p. 132, 15.