Hmm, im not really sure what you mean.. maybe you could explain a bit about the conversation you had where the term was bought up. Here in an operations environment we use the term GMC as a delay reason, GMC as we have it means Ground Movement Control. For example our aircraft is denied pushback for 10 minutes due to another aircraft pushing/passing behind we would put the delay down to GMC for 10 mins.
Hope this helps.... hmmm
OJ
Edit; Thinking about it, maybe in an Airfield environment it could refer to the aerodrome having a Ground Movement Controller, basically someone to direct the aircraft on the ground (down taxiways, to parking stands/runway etc) before they are handed over to the tower controller for departure.. just a thought...
OJ