Compression \Com*pres"sion\, n. [L. compressio: cf. F. compression.] 1. The act of compressing, or state of being compressed. ``Compression of thought.'' --Johnson.
2. (Computers) reduction of the space required for storage (of binary data) by an algorithm which converts the data to a smaller number of bits while preserving the information content. The act of compressing [3].
Note: Compression may be {lossless compression}, in which all of the information in the original data is preserved, and the original data may be recovered in form identical to its original form; or {lossy compression}, in which some of the information in the original data is lost, and decompression results in a data form slightly different from the original. {Lossy compression} is used, for example, to compress audio or video recordings, and sometimes images, where the slight differences in the original data and the data recovered after {lossy compression} may be imperceptable to the human eye or ear. The {JPEG} format is produced by a {lossy compression} algorithm. [PJC]
JPEG \JPEG\ n. [Acronym from Joint Picture Experts Group.] (Computers) A standardized format for storing graphic data in binary computer files, allowing over 16 million different colors. It allows for lossy compression, i. e. the compression of data into a form which re-expands into an image close, but not identical to the original image. Files stored in this format usually carry the extension jpg or jpeg. Compare {GIF}. [PJC]