Decompression

Noun

1. The process of decompressing.

   "The decompression of large data files may take a while."

2. The restoration to atmospheric pressure of a person who has spent time under higher pressure (such as a diver).
3. A mode of operation of some internal combustion engines which reduces the engine's compression ratio, making it easier to start but significantly increasing fuel consumption.
4. The relief of pressure on a body part by surgery.