The color is named after the fruit. The English word comes from the Anglo-Norman and Middle French orenge, which in turn is from Italian, where it appears in several forms, including arancio, narancia, and naranza. The Italians acquired the word and the fruit from Arab traders. In Arabic, the word is naranj. The Sanskrit word is naranga and in Tamil it is naram, so it is likely the Arabs obtained the fruit from India. Oranges were probably originally cultivated in southeast Asia.
The word’s English appearance is sometime before 1400 when it appears in J. Mirfield’s Sinonoma Bartholomei:
Citrangulum pomum, orenge.
It’s use to mean the color comes some 150 years later, when it appears in the Great Britain Statutes at Large of 1557:
Coloured cloth of any other colour or colours...hereafter mentioned, that is to say, scarlet, red, crimson, morrey, violet, pewke, brown, blue, black, green, yellow, blue, orange, [etc.].
The House of Orange (referring to the Dutch royal family or William and Mary of England) and the use of the term in Irish politics is of a different origin. This use derives from the town of Orange on the Rhone River in France and is etymologically unrelated to the color or the fruit. The House of Nassau, the Dutch royal family, acquired the principality of Orange in 1544. The province was returned to France in 1713, but the name was retained by the Dutch royalty. The Protestant William of Orange, or William III, co-ruled Britain with his wife Mary after her father, the Roman Catholic James II, was deposed in the Glorious Revolution of 1688. The use of orange in Irish politics dates to this time, when Irish Protestants began using his name and coat of arms to denote loyalty to the crown.
(Source: Oxford English Dictionary, 3rd Edition)
Copyright 1997-2015, by David Wilton