While there is a great deal of disagreement in the brewing world on this subject, at one time, porter was considered an alternative name for stout. It was originally used in the 18th century. Historically, there are no differences between stout and porter, though there has been a tendency for breweries to differentiate the strengths of their dark beers with the words "extra", "double" and "stout". The term "stout" was initially used to indicate a stronger porter than other porters issued by an individual brewery — though one brewery's porter could easily be stronger than a neighbouring brewery's stout. Though not consistent, this is the usage that was most commonly employed
