Compression refers to the process of reducing the size of data, files, or digital content by encoding information more efficiently. This technique is commonly used to save storage space, speed up data transmission, and optimize performance across various applications, such as images, audio, video, and software files. Compression can be either lossless, preserving all original data, or lossy, where some information is discarded to achieve higher size reduction. The choice of compression method depends on the specific requirements for quality, speed, and storage.