Muzak was a company started in the early 20th century by the American Major General George O'Squier. Apparently he liked the sound of the company name 'Kodak' and therefore modeled his own company's name after it, hence 'Muzak'. During WWI O'Squier perfected the method of transmitting music across electrical wires; however, by the time he had perfected this technology, radio had already been firmly established as a means of transmitting music. O'Squier then sought out a different market in background music that could exploit the technology he perfected.
Essentially Muzak was the pioneering company in background music supply. With the industrial boom and the rapid growth of cities with skyscrapers, Muzak became synonymous with elevator music as they were the ones providing the music for the long trip up these mountainous buildings. Elevator music is therefore commonly referred to as 'Muzak'. Elevator music is usually a soft, unobtrusive and typically jazz style of music used to provide a calm relaxed atmosphere without distracting people from their thoughts or task.
An interesting point on Muzak's catalogue is that they did not have the recordings and rights to a lot of music when the company was started so they made their own recordings to build up their library. Muzak had a collection of some of the rarest and valuable recordings including a number from notable musicians from the jazz era.
Thanks to O'Squier's pioneering technology to share music without the use of radio, there will never have to be a moment of awkward silence shared between two people in an elevator ever again.
Trex, E. 2011. Muzak History: The Background Story On Background Music. Retreived from http://mentalfloss.com/article/28274/muzak-history-background-story-background-music
Ryan, L. 2012. What Is Muzak?. Retrieved from https://melodicramblings.wordpress.com/2012/09/24/what-is-muzak/