ASME Y14.5 : Dimensioning and Tolerancing
Two or more features to which a position or profile geometric tolerance is applied and that are grouped by one of the following methods: nX, n COAXIAL HOLES, ALL AROUND, ALL OVER, between A and B (A ? B), from A to B (A ? B), n SURFACES, simultaneous requirements, or INDICATED, where n in these examples represents a number.
See Also:
Feature, Profile, Geometric Element, Tolerance