boullion / bullion are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
boullion: NA
bullion: (noun) a mass of precious metal. (noun) gold or silver in bars or ingots.
boullion: b·UW·l·y·ah·n
bullion: b·UH·l·y·ah·n
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)