The term popular music belongs to a number of musical genres "having wide appeal" and typically distributed to large audiences through the music industry. These forms and styles can be enjoyed and performed by people with little or no musical training. It stands in contrast to both art music and traditional music. Art music was historically disseminated through the performances of written music, although since the beginning of the recording industry, it is also disseminated through recordings. Traditional music forms such as early blues songs or hymns were passed orally, or to smaller, local audiences. The original application of the term is to music of the 1880s Tin Pan Alley period in the United States. Although popular music sometimes is known as "pop music", the two terms are not interchangeable. Popular music is a generic term for music of all ages that appeals to popular tastes, whereas pop music usually refers to a specific musical genre within popular music. The song structure of popular music commonly involves the verse, chorus or refrain, and bridge as the different sections within a piece. With digital access to music, some popular music forms have become global, while others have wide appeal within the culture of origin. Through hybridity, or mixture across musical genres, new popular music forms are able to be manufactured to reflect the ideals of a global culture. The examples of Africa, Indonesia, and the Middle East explain how hybridity can develop into new forms of popular music.