The color orange was named after the fruit, not vice-versa

The word orange is derived from Sanskrit nāraṅgaḥ "orange tree" and in Telugu "Naringa". The Sanskrit word was borrowed into European languages through Persian nārang, Armenian nārinj, Arabic nāranj, (Spanish naranja and Portuguese laranja), Late Latin arangia, Italian arancia or arancio, and Old French orenge, in chronological order. The first appearance in English dates from the 14th century.

The forms starting with n- are older; this initial n- may have been mistaken as part of the indefinite article, in languages with articles ending with an -n sound (e.g., in French une norenge may have been taken as une orenge). The name of the colour is derived from the fruit, first appearing in this sense in 1542.

(Via "Oranges and Peanuts for Sale," Harper's Magazine, June 2009.)