from The American Heritage® Dictionary of the English Language, 4th Edition
- A trademark used for recorded background music transmitted by wire or radio, as to places of business, on a subscription basis.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- proper n. Recorded background music transmitted by wire, radio or compact disc on a subscription basis to places of business, etc.
- proper n. Easy listening music in general.
Derived from a play on the word "music" incorporating the "-ak" from Kodak, by Muzak Corporation (later Muzak Holdings, LLC), a company which pioneered the creation of the genre. (Wiktionary)