A la carte is when ordering a meal, refers to ordering just one single food item. A la carte steak would mean just the steak without any sides.
Other definition:
a la carte is referring to meals, an indication that each dish is priced separately; also that a choice of meals may be vailable, such as on a tour
a la carte. Fr. Literally, "from the menu." 1. In restaurants, indicates that each dish ordered will have a separate price. Also, used in tour literature to indicate a choice of dishes will be available. 2. By extension, any travel products that can be purchased separately, as opposed to as a package.