The word Muzak has been a registered trademark since December 21, 1954, of Muzak LLC, although it dominated the market for so many years that the term is often used (especially when used with lowercase spelling) as a generic term for all background music. The term Muzak is – at least in the United States – often used as a term for most forms of background music, regardless of the source of the music, and may also be known as „elevator music“ or „lift music“.