Plain English Meaning
A recorded radio message that tells pilots the latest airport conditions before they call the tower, so the controllers don't have to repeat the same information to every aircraft.
Full Definition
A continuous broadcast of recorded non-control airport and weather information for arriving and departing aircraft at busier airports. Each broadcast is updated when conditions change and is identified by a sequential phonetic letter (Information Alpha, Bravo, Charlie, and so on). It typically includes the current weather, active runways, approaches in use, and any relevant notices to airmen.
Context Anchor
Pilots use it before departure, before , and when planning radio calls at airports that provide the . It is commonly called .