Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† 1. bu = βου, a Greek prefix, which, in composition, expresses the idea of greatness: Graeci assueti magnis et amplis rebus praeponere βου, a magnitudine scilicet bovis. Hic est, quod grandes pueri βούπαιδας appellant et mariscam ficum βούσυκον, Paul. ex Fest. p. 109 Müll.; Varr. R. R. 2, 5, 4 [cf. Engl. horse-cucumber, elephant folio, etc.].
‡ 2. bu, v. bua.