Disco means a genre of the dance music and this has charted high in the mid-1970s. This genre got the popularity peaked in the late 1970s. In addition, disco was catering in the late years of 1960s and the early years of 1970s to the African American, gay people, psychedelic, and other communities in New York City and in Philadelphia. The styles of it are funky and various and it is originally from Latin and Salsa mix with pop rock. The typical instruments that they used are electric guitar, bass, a machine drum, string and horn section or even a solo instrument like percussion.
Since the disco can be, mix in different varieties of music; the musicians remake some old Christmas songs that could be funky to dance and sing. In this idea of remixing the song, the song changes to disco Christmas songs, but the tune and the lyrics are still there, it is just remixing the old one to new way of listening.