CD-i is an entertainment and information system that plays digital data stored on a compact disc. The CD-i player connects to a television set or to a color monitor. You may also connect a CD-i player to your stereo system for higher quality audio. CD-i discs are used in the home, in education, and in business.

CD-i is the first multimedia technology aimed at a mass audience. CD-i allows the multimedia designer to blend different media in the form of visual, audio, graphic, and computer data into a single experience for the user. CD-i allows the user to interact with the information on the disc and to guide the presentation in a meaningful way. CD-i lends itself to informational titles, games, encyclopedias, educational material, and many business applications. With the addition of a special hardware module, CD-i players can now play feature films and other video material.

Besides CD-i discs, CD-i player can play Compact Disc-Digital Audio (CD-DA), CD+Graphics (CD+G), Photo CD, and, with a Digital Video cartridge, Karaoke CD and Video CD discs. A CD-i player is a self-contained computer system with specific video, audio and control hardware and software, and an optical disc drive.

CD-i technology was developed jointly by N.V. Philips of the Netherlands and Sony Corporation in Japan. The primary goal of the two companies was to develop a worldwide standard so that CD-i discs would run on all CD-i players anywhere in the world. To that end, they published the CD-i Full Functional Specification, which is more commonly known as the Green Book. Any changes or extensions to the CD-i standard must be approved by both Philips and Sony before they become an official part of the specification.