commercial unit

Number or quantity in which an item is sold as a single entity, and a sub-division of which will impair the item's character, usefulness, and/or value. It may denote a single item (such as a machine or property), a set of articles (such as an instrument-set or tool-set), or a quantity (such as a ream of paper or a truck-load of a commodity), or any other unit of sale or measurement.