The name café au lait is a French term that means “coffee with milk”. It traditionally refers to any coffee that contains coffee and milk, not to a specific beverage. The meaning of the term differs between Europe and the United States, butin both cases it means some kind of coffee with hot milk added.
The café au lait term is used in contrast with the caffè latte to indicate whether the beverage has been prepared using the French or Italian tradition. The café au lait in this instance is served in a cup and the caffè latte is served in a glass.
However, both the café au lait and the caffè latte have little bearing in the French and Italian coffee cultures. The terms are used far more commonly internationally.
In the United States, a café au lait is typically prepared with strong brewed filter coffee or French press coffee. Steamed milk is then added on top. A lattè, on the other hand, is always brewed in the States using an espresso machine.
A café au lait normally signifies the use of heated milk compared to a white coffee, in which the milk is added cold to the coffee.