I'm not sure about this but there might be some people doesn't know the mean of some military terms during some military RP. Here is some simple explainations about those terms.

CASEVAC:Casualty Evacuation:It's about emergency patient evacuation of casualities from a combat zone.It can be done by both ground and air.

MEDEVAC or Medivac:Medical Evacuation:It's about timely and effcient movement and en route care provided by medical personnel and can be done by both air and ground.

10 Mikes: 10 Minutes.

2 klicks: 2 kilometers.

Fire mission: Fire Support(related to Air Support).

Alpha Delta 250147:Coordinates of artillery support.

Bingo on fuel:It mean that their fuel are almost out of fuel and they need take a time to refuel.This is related to aircrafts,especially AC-130.

RTB:Return To Base/Retract To Base.

ROE:Rules Of Engagement:This is the rules in military that will tell you about when you are allowed to engage with hostiles.