A brigantine is a two-masted vessel with her foremast fully square rigged and her mainmast rigged with both a fore-and-aft mainsail (usually a gaff sail) and square topsails (and possibly topgallant sails).
A vessel that fits the above definition is a true brigantine. However, today the term brigantine usually means something else, namely a vessel that is more accurately called a hermaphrodite brig, one with the foremast square rigged and the mainmast fore-and-aft rigged without any square sails. There is currently only one sailing true brigantine in the world, the Eye Of The Wind.
The brigantine can be said to belong to the family of schooners; in Scandinavian languages the brigantine is sometimes referred to as a `schooner brig.´