The term - World Music - has been used, abused, and redefined several different ways over its relatively short life existence in the English language dictionary.
Originally, we would use the term "ethnomusicology" to describe music from a vast number of cultures. I wasn't a fan of this term because it always sounded too scholastic and "snooty". Ironically, it was an ethnomusicologist that coined the term "world music". Around the mid-1980s, this term became more widespread, mainly within the music industry. Today, it still isn't a household term like rock, classical or country, but most people can identify with the term.
World Music represents so much more than just a genre of music, it represents history, diversity, culture and, in most cases, tells a story. For example, in Armenian music, much of the folk music I perform represents village life both sad and happy. It describes a beautiful girl such as the song Siroon Aghchig, written by one of the Armenian master musicians Udi Hrant. This song, like many others, tells the story of the people. Very simplistic lyrics which describe every day life or perhaps what a musician is feeling at that moment he/she writes a song. Perhaps the song describes war or death. The common element which seems to flow through most of this music is the stories they tell are not unique.
Today, world music has a broad definition and any song which includes the instrumentation indigenous to that particular culture is labeled world music.
Even my children get to experience world music through the sights and sounds of Baby Einstein.
World music has made mainstream within the recorded music industry in the last twenty years. Musicians from Sting to Yo Yo Ma have brought world music to the forefront. Yo Yo Ma organized the Silk Road Project that encompasses many cultures and instrumentation, Sting ccomposed Desert Rose and even classical violinist Itzhak Perlman dabbled into his culture by releasing an album of Klezmer music a number of years ago.
I encourage you to seek out world music, give it a try and let me know what you think!