- a radiogram.
- Older Use. a message carried by aircraft; an airmail letter.
- a diagram for analyzing thermodynamic processes in the atmosphere.
- the record of an aerograph.
- a sheet of lightweight paper, bearing an official postal stamp imprint, that is folded to form its own envelope and can be sent via airmail at a special, low rate because of its standard size, light weight, and lack of enclosures.
- Also called: air letter an airmail letter written on a single sheet of lightweight paper that folds and is sealed to form an envelope
- another name for radiotelegram