Compression (noun)

1. The action or process of compressing or being compressed.
2. The reduction in volume (causing an increase in pressure) of a fluid or gas as it is forced into a smaller space.

Origin:

From late latin compressio(n-), from compress- ('pressed together').

Examples:

1. Compression of the spring caused it to release its energy.
2. The compression of the air in the tire helps to maintain its shape.
3. The video file was reduced in size using compression technology.