When is the word mil used in French?

Mil is the French word for "mille" or "thousand". It is used in the same way as the English word "thousand", to refer to a quantity of one thousand. For example, "il y a mil personnes dans le stade" means "there are one thousand people in the stadium". Mil can also be used in compound words, such as "millier" (thousandth) and "millénaire" (millennium).