minimum enroute ifr altitude. the lowest published altitude between radio fixes that meets bstacle clearance requirements between those fixes and in many countries assures acceptable navigational signal coverage. The MEA applies to the entire width of the airway, segment, or route between the radio fixes difining the airway segment route.
an altitude depeicted on an instrument approach procedure chart requiring the aicraft to maintain altitude at the depicted value.
maximum authorized altitude (MAA) a publised altitude representing the maximum usable altitude or flight level for an airspace structure or route segment
Minimum crossing altitude. the lowest altitude at a certain fixes at which an aircraft must cross when proceeding in the direction of highter minimum entroute ifr altitude.
minimum desent altitude/height a specified altitude or height in a non-precision approach or circling approach below which descent may not be made without visual reference.