Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
lūtra (lȳtra), ae, f. [luo], an otter, Plin. 8, 30, 47, § 109; 32, 11, 53, § 144; form lytra, Varr. L. L. 5, § 79 Müll.
lytra, v. lutra.