Motown Record Company, L.P., also known as Tamla-Motown outside of the United States, is a record label specializing in the musical genres of R&B, pop, soul music, and hip-hop music. The label was originally based out of Detroit, Michigan ("Motor Town"), and is named for the city's association with the automobile industry. Motown was the first record label owned by an African-American to become a widespread international success, and played an important role in the integration of popular music.

Detroit: the largest city in Michigan and a major Great Lakes port; center of the United States automobile industry; located in southeastern Michigan on the Detroit river across from Windsor
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en.wikipedia.org/wiki/Motown

In the 1960s it was the most successful proponent of what came to be known as The Motown Sound, a style of soul music with distinctive characteristics including the use of tambourine along with drums, bass instrumentation, and a 'call and response' singing style originating in gospel music.
The Motown Sound
While there were popular African American musicians prior to the 1960s, including Louis Armstrong, Ethel Waters, Mamie Smith, Ella Fitzgerald, Nat King Cole, Louis Jordan, and Chuck Berry, Motown was the most consistently chart-topping genre until hip-hop. In contrast to previous genres of black popular music, Motown soul used African-American performers instead of grooming white musicians for crossover fame. It was also the first genre of African-American popular music to move beyond simple lyricisms into the realm of socio-political topics, allowing for a wide range of African-American viewpoints to be expressed in song.

The Motown Sound was also defined by the use of orchestration, string sections, charted horn sections, carefully arranged harmonies and other more refined pop music production techniques. It was also one of the first styles of pop music of that era wherein girl groups were showcased as an act, as opposed to individual female artists. Such as The Supremes, Martha and the Vandellas and the Marvelettes.

http://dictionary.laborlawtalk.com/Motown#The_Motown_Sound

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Note added at 13 mins (2006-11-04 14:22:04 GMT)
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R&B => Rhythm and Blues

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