Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† lăgēna (also lăgaena, lăgoena, and lăgōna), ae, f., = λάγηνος, a large earthen vessel with a neck and handles, a flask, flagon, bottle: quasi tu lagenam dicas, ubi vinum solet Chium esse, Plaut. Curc. 1, 1, 78; Cic. Fam. 16, 26, 2; Quint. 6, 3, 10; Hor. S. 2, 8, 41; 81; id. Ep. 2, 2, 134; Juv. 12, 60; 14, 271 et saep.
Also made of other materials, Plin. 16, 31, 56, § 128: Syra nigri defruti, of glass, Mart. 4, 46, 9.