A plimsoll shoe, plimsoll, plimsole or pumps (British English; see other names below) is a type of athletic shoe with a canvas upper and rubber sole developed as beachwear in the 1830s by the Liverpool Rubber Company.
Plimsolls had solid rubber soles about 8 or 9mm thick, to which the canvas was glued without coming up the sides (as on trainers). The effect when running was not dissimilar to running without shoes.
The shoe was originally, and often still is in parts of the United Kingdom, called a "sand shoe" and acquired the nickname "plimsoll" in the 1870s. This name derived, according to Nicholette Jones's book The Plimsoll Sensation, because the coloured horizontal band joining the upper to the sole resembled the Plimsoll line on a ship's hull, or because, just like the Plimsoll line on a ship, if water got above the line of the rubber sole, the wearer would get wet.
In the UK plimsolls are commonly worn for schools' indoor physical education lessons. Regional terms are common: in Northern Ireland and central Scotland they are sometimes known as gutties; "sannies" (from 'sand shoe') is also used in Scotland. In parts of the West Country and Wales they are known as "daps" or "dappers". In London, the home counties, much of the West Midlands,the West Riding of Yorkshire and north west of England they are known as "pumps". There is a widespread belief that "daps" is taken from a factory sign – "Dunlop Athletic Plimsoles" which was called "the DAP factory". However, this seems unlikely as the first citation in the Oxford English Dictionary of "dap" for a rubber soled shoe is a March 1924 use in the Western Daily Press newspaper; Dunlop did not acquire the Liverpool Rubber Company (as part of the merger with the Macintosh group of companies) until 1925. Plimsolls were issued to the British military (called 'road slappers' by the common soldiery) until replaced by trainers in the mid-80's. If white they required hours of application of shoe whitener, if black they were required to be polished until they gleamed.