Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

armilla, ae, f. [acc. to Paul. ex Fest. p. 25 Müll., from armus; acc. to Prisc. p. 1220 P., from arma].

  1. I. A circular ornament for the arm, a bracelet, armlet, for men and women: armillae, quae bracchialia vocantur, Cic. ap. Prisc. l. c.: Ubi illae armillae sunt, quas unā dedi? Plaut. Men. 3, 3, 13; cf. Dig. 34, 2, 26: armillis decoratus, Quadrig. ap. Gell. 9, 13, 7: manipulum hastatorum armillis donavit, Liv. 10, 44; Plin. 28, 11, 47, § 172: armillas posui in manibus ejus, Vulg. Gen. 24, 47; ib. Ezech. 23, 42: monilia et armillae, ib. Isa. 3, 19.
  2. II. An iron hoop, ring, ferrule, Cato, R. R. 21, 4; Vitr. 10, 6.

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.