late 14c., in reference to the fruit of the orange tree (late 13c. as a surname), from Old French orange, orenge (12c., Modern French orange), from Medieval Latin pomum de orenge, from Italian arancia, originally narancia (Venetian naranza), an alteration of Arabic naranj, from Persian narang, from Sanskrit naranga-s "orange tree," a word of uncertain origin.
Not used as a color word in English until 1510s (orange color), "a reddish-yellow color like that of a ripe orange." Colors similar to modern orange in Middle English might be called citrine or saffron. Loss of initial n- probably is due to confusion with the definite article (as in une narange, una narancia), but also perhaps was by influence of French or "gold." The name of the town of Orange in France (see Orangemen) perhaps was deformed by the name of the fruit. Orange juice is attested from 1723.
The tree's original range probably was northern India. The Persian orange, grown widely in southern Europe after its introduction in Italy 11c., was bitter; sweet oranges were brought to Europe 15c. from India by Portuguese traders and quickly displaced the bitter variety, but only Modern Greek still seems to distinguish the bitter (nerantzi) from the sweet (portokali "Portuguese") orange.
Portuguese, Spanish, Arab, and Dutch sailors planted citrus trees along trade routes to prevent scurvy. On his second voyage in 1493, Christopher Columbus brought the seeds of oranges, lemons and citrons to Haiti and the Caribbean. Introduced in Florida (along with lemons) in 1513 by Spanish explorer Juan Ponce de Leon. It was introduced to Hawaii in 1792.
Since Middle English restricted to use as the common name of the viper, the only poisonous British reptile (not generally fatal to humans), then by extension applied to venomous or similar snakes elsewhere (puff-adder, etc.). The modern form represents a faulty separation 14c.-16c. of a nadder into an adder, for which see also apron, auger, nickname, orange, humble pie, aitchbone, umpire. Nedder is still a northern English dialect form. Folklore connection with deafness is via Psalms lviii.1-5. The adder is said to stop up its ears to avoid hearing the snake charmer called in to drive it away.
1796 in reference to members of a secret politico-religious society founded 1795 in Belfast to promote Protestant power in Northern Ireland, named for William of Orange (who became King William III of England and triumphed in Ireland at the head of a Protestant army at the Battle of the Boyne), of the German House of Nassau. His cousins and their descendants constitute the royal line of Holland.
The name is from the town of Orange on the Rhone in France, which became part of the Nassau principality in 1530. Its Roman name was Arausio, which is said in 19c. sources to be from aura "a breeze" and a reference to the north winds which rush down the valley, but perhaps this is folk etymology of a Celtic word. The name subsequently was corrupted to Auranche, then Orange.
The town has no obvious association with the fruit other than being on the road from Marseilles to Paris, along which masses of oranges were transported to northern France and beyond. In this roundabout way the political/religious movement of Northern Irish Protestantism acquired an association with the color orange, the Irish national flag acquired its orange band, and Syracuse University in New York state acquired its "Otto the Orange" mascot.