Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† zīzyphum or zīzĭphum, i, n., = ζίζυφον, the jujube. Plin. 15, 14, 14, § 47; 17, 10, 14, § 74; 21, 9, 27, § 51.