Input (grade 13): The term is further used more generally to refer to an expanse surrounding some object; for example, an airport can have a concrete "apron" around it, where planes and other vehicles can move about.
Output (grade 7): Other meanings The term "apron" is also used to refer to an area around some object. For example, an airport can have a concrete "apron" around it, where planes and other vehicles can move about.