brig1Pronunciation: /brɪg/Definition of brig noun 1a two-masted square-rigged ship, typically having an additional lower fore-and-aft sail on the gaff and a boom to the mainmast. 2 informal a prison, especially on a warship. Origin: early 18th century: abbreviation of brigantine (the original sense)brig in other Oxford dictionaries Definition of brig in the US English dictionary