[computing]
The process of reducing the size of a file or database. Typically clarified as lossy (high compression/some data loss) or lossless (lower compression/larger file size). Compression improves data handling, storage, and database performance. Examples of compression methods include run-length encoding, and wavelets.
[Esri software]
A process that removes unreferenced rows from geodatabase system tables and user delta tables. Compression helps maintain versioned geodatabase performance.