A dark beer made using roasted malt or roasted barley, hops, water and yeast. Stouts were traditionally the generic term for the strongest or stoutest porters, typically 7% or 8%, produced by a brewery.

The first known use of the word stout for beer was in a 1677 document dated 1677, the sense being that a stout beer was a strong beer not a dark beer. The name porter was first used in 1721 to describe a dark brown beer that had been made with roasted malts. Because of the huge popularity of porters, brewers made them in a variety of strengths. The beers with higher gravities were called stout porters, so the history and development of stout and porter are intertwined and the term stout has since become firmly associated with dark beer, rather than just strong beer.

Sweet milk stouts became popular in Britain in the years following WWI, although their popularity declined towards the end of the 20th century.

Stout is sometimes considered a sub-type of ale.