AIP

• Aeronautical Information Publication

  ATC

• aeronautical information publications (In General)

  General

AIP has 2 meanings; the right one depends on context. A weather report, a NOTAM or an ATC clearance. Got a NOTAM full of contractions? Paste it into the decoder.

Source: FAA Order JO 7340.2 Contractions. Not for operational use.