Cajun pertains to a group of people and an area of America, mainly Louisiana. The people are descendants of French Settlers who were exiled from Nova Scotia (Arcadie) and still have a dialect which includes French although spoken in a non-French accent.
The region has a particular music and dance form. The music is Melodeon based and has a characteristic double beat, especially on forms such as the Two Step. The Fiddle and Triangle feature as stock instruments.
Cajun music is often linked with Zydeco, both being Melodeon based and from Louisiana but the two genres are regarded as different.