From: The Guinness Drinking Companion by Leslie Dunkling (1992)
     Guinness Publishing; ISBN 0-85112-988-9 "In the London Ale-Houses and
     taverns of the early 18th Century it was common to call for a pint of
     "Three threads", meaning a third of a pint each of ale, beer, and
     twopenny (the strongest beer, costing twopence a quart). A brewer
     called Harwood had the idea of brewing a beer that united the
     flavours of all three. He called this beer "Entire". This was about
     1720.

     Harwood's Entire was highly hopped, strong, and dark. It was brewed
     with soft rather than hard water. Within a few years Entire was also
     being referred to as "Porter" (short for porter's ale) because the
     porters of the London street markets were especially fond of it.
     Porter that was extra strong was known as "Stout Porter", and
     eventually "Stout"."