multiplexed (MX)

A term describing a device that has pins used for different purposes at different times as a function of one or more of its control inputs. The signal groups that are multiplexed onto a common pin set are given together, as in AA MX signifying address multiplexed with address or ADQ MX signifying address multiplexed with data in and data out.

References: 

JESD21-C, 1/97