An ethnic group or ethnicity is a category of people who identify with each other based on common ancestral, social, cultural or national experience. Unlike most other social groups, ethnicity is primarily an inherited status. Membership of an ethnic group tends to be defined by a shared cultural heritage, ancestry, origin myth, history, homeland, language and/or dialect, symbolic systems such as religion, mythology and ritual, cuisine, dressing style, art, and physical appearance.

Ethnic groups, derived from the same historical founder population, often continue to speak related languages and share a similar gene pool. By way of language shift, acculturation, adoption and religious conversion, it is possible for some individuals or groups to leave one ethnic group and become part of another (except for ethnic groups emphasizing racial purity as a key membership criterion).

Ethnicity is often used synonymously with ambiguous terms such as nation or people.

Depending on which source of group identity is emphasized to define membership, the following types of (often mutually overlapping) groups can be identified:

Folk music includes both traditional music and the genre that evolved from it during the 20th century folk revival. The term originated in the 19th century but is often applied to music that is older than that. Some types of folk music are also called world music.

Traditional folk music has been defined in several ways: as music transmitted orally, or as music with unknown composers. It has been contrasted with commercial and classical styles. One meaning often given is that of old songs, with no known composers; another is music that has been transmitted and evolved by a process of oral transmission or performed by custom over a long period of time.

Starting in the mid-20th century a new form of popular folk music evolved from traditional folk music. This process and period is called the (second) folk revival and reached a zenith in the 1960s. This form of music is sometimes called contemporary folk music or folk revival music to distinguish it from earlier folk forms. Smaller similar revivals have occurred elsewhere in the world at other times, but the term folk music has typically not been applied to the new music created during those revivals. This type of folk music also includes fusion genres such as folk rock, folk metal, electric folk, and others. While contemporary folk music is a genre generally distinct from traditional folk music, in English it shares the same name, and it often shares the same performers and venues as traditional folk music. Even individual songs may be a blend of the two.