Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. bēta, ae (bētis, is, Ser. Samm. 54, 9), f. [hence Fr. bette; Engl. beet], a vegetable, the beet: Beta vulgaris, Linn.; Plin. 19, 8, 40, § 132; 20, 8, 27, § 69; Col. 10, 254; 10, 326; 11, 3, 17 and 42; Pall. Febr. 24, 10; * Plaut. Ps. 3, 2, 26; * Cic. Fam. 7, 26, 2; cf. * Cat. 67, 21; Mart. 13, 13; 3, 47, 9; Isid. Orig. 17, 10, 15.
† 2. bēta, n. indecl. (beta, ae, f., Aus. Technopaegn. c. Litt. Mon. v. 13), = βῆτα, the Greek name of the second letter of the alphabet (pure Lat. be; v. B): hoc discunt omnes ante alpha et beta puellae, * Juv. 14, 209.
Hence, prov., the second in any thing (as alpha is the first), Mart. 5, 26.