The original use of the phrase “World Music” was credited to Ethnomusicologist/Musicologist "Robert E. Brown" who used it in the 1960s.
The term became common place during the 1980s, it became a marketing term in the media and the music industry, and it is generally used in a discriminatory and problematic fashion to classify any kind of non-Western music, even including some Western styles such as Celtic Folk music.
A basic and more accurate definition of "World Music" would be;- "music from all the music in the world", which pretty much renders the term meaningless as a Music Genre, outside the realm of marketing.
The term also is taken erroneously as a classification of music that combines Western popular music styles with one or many genres of Non-Western music that were previously described as Folk music or Ethnic Music, however, the correct term for this style would be either "Worldbeat" or possibly "World Fusion".
One of the finest examples of "Worldbeat"/"World Fusion"/"World Music" would be "Transglobal Underground"