Shuffle beat

In jazz and related musical styles, the term swing has two main uses. Colloquially, it is used to describe the sense of propulsive rhythmic "feel" or "groove" created by the musical interaction between the performers, especially when the music creates a "visceral response" such as feet-tapping or head-nodding (see pulse). The term is also used more specifically, to refer to a particular rhythmic technique (most commonly associated with jazz but also used in other genres) that involves alternately lengthening and shortening pulse-divisions.

Like the term "groove", which is used to describe a cohesive rhythmic "feel" in a funk or rock context, the concept of "swing" can be hard to define. Indeed, some dictionaries use the terms as synonyms: "Groovy ... denotes music that really swings." The Jazz in America glossary defines it as "when an individual player or ensemble performs in such a rhythmically coordinated way as to command a visceral response from the listener (to cause feet to tap and heads to nod); an irresistible gravitational buoyancy that defies mere verbal definition."

Swing has been called "the most debated word in jazz". When jazz performer Cootie Williams was asked to define it, he joked, "Define it? I'd rather tackle Einstein's theory!" When Louis Armstrong was asked on the Bing Crosby radio show what swing was, he said, "Ah, swing, well, we used to call it syncopation—then they called it ragtime, then blues—then jazz. Now, it's swing. Ha! Ha! White folks, yo'all sho is a mess."Benny Goodman, the 1930s-era bandleader nicknamed the "King of Swing", called swing "free speech in music", whose most important element is "the liberty a soloist has to stand and play a chorus in the way he feels it". His contemporary Tommy Dorsey gave a more ambiguous definition when he proposed that "Swing is sweet and hot at the same time and broad enough in its creative conception to meet every challenge tomorrow may present."Boogie-woogie pianist Maurice Rocco argues that the definition of swing "is just a matter of personal opinion". When asked for a definition of swing, Fats Waller replied, "Lady, if you gotta ask, you'll never know."

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