Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dŭŏ-dēni, ae, a, distr. num., twelve each; twelve: uxores habent deni duodenique inter se communes, Caes. B. G. 5, 14, 4: duodena describit in singulos homines jugera, Cic. Agr. 2, 31, 85; Liv. 5, 33; cf.: fossa duplex duodenūm pedum, Caes. B. G. 7, 36, 7: milia, id. ib. 7, 75, 3: astra, Verg. G. 1, 232; cf. signa, Ov. M. 13, 618: nec inveniuntur qui velint debere rei publicae, praesertim duodenis assibus, at twelve per cent., Plin. et Traj. Epist. 54, 1.