Riding

Apart from the uses of riding as the -ing participle and the verbal noun of the verb 'to ride', there is a less common noun, '[a] riding'. This is derived from the Old Norse þriðjung-r third part, from þriði, 'third', through (conjectured) Old English þriðing or þriding, where the initial consonant was absorbed by the preceding '-t' or '-th' of east, west, north, or south. Early forms trithing and thrithing could still be seen up to the 17th century.

Compare farthing, from OE féorðing or féorðung, from féorð- 'a fourth' cf. Old Norse fiórðungr, used for 'a small part [ofanything]', 'a quarter [usually of a unit of money, sometimes of a measure of land]'. In the last two centuries, a farthing meant a quarter of a penny. This virtually valuelss item of currency ceased to be legal tender in 1961.

• A Riding was a common term in the Danelaw to mean an administrative unit, a third part of a larger whole, for example of most counties. This usage currently survives only in Yorkshire, and even here is now colloquial and informal, the official local government nomenclature having been abolished in 1974. The successor names are North Yorkshire, South Yorkshire and West Yorkshire