in cookery, a mixture of diced vegetables, 1815, from French, evidently named for Charles Pierre Gaston François, duc de Mirepoix (1699-1757), French diplomat. The concoction supposedly was created by his head chef and named in his honor during the reign of Louis XV, one of the grand epochs of French cookery, when it was the style of the aristocracy to have dishes named in their honor.
MIREPOIX.—It is probable that one of these days the common sense of mankind will rise in rebellion against this word and abolish it. What is the Duke of Mirepoix to us because his wife was amiable to Louis XV.?
If she be not fair to me,
What care I how fair she be?
The Duke of Mirepoix made himself convenient to the king, and his name is now convenient to the people—the convenient name for the faggot of vegetables that flavours a stew or a sauce. ["Kettner's Book of the Table," London, 1877]