World War II and the Greatest Generation are either in battle on European or Pacific fronts, or on leave, home, in the US. Swing was all the rage. The Jitterbug only a decade before (1930s) was not taught because of previous values. The music was faster, with horns, strings, even orchestral, and so, by the 40s, swing dance was being taught all over America. The Lindy Hop was one of the popular swing dances, and derived from the Lindy Hop was the Jitterbug. Its name is of speculation. Some said the moves of the Jitterbug looked like an alcoholic in recovery; others said it was an ethnic slur, now unknown. While many rumors abound, the name comes from Henry Alexander White, also known as "Father White," a trombonist, drummer, and arranger, who worked with the likes of Duke Ellington, Elmer Snowden, and Cab Calloway. A one Swayze wrote a song after hearing White's name, "The Jitterbug."
As a trivia note, the first song written for The Wizard of Oz was a song entitled "The Jitterbug."
Originally, Jitterbug was an umbrella term for all the different Swing dances in cities and states throughout the US. However, others argue that Jitterbug does not equal Swing dances. In other words, the term Jitterbug is not all encompassing, and as mentioned above, was rooted in a particular swing dance, the Lindy Hop. Either way, in contemporary times, one would choose between the Lindy Hop or the Jitterbug, as well as many other variants of Swing.
The moves of the Jitterbug strictly are, in choreographed terms, back-step-forward-touch-step-touch. It's on a six-count measure. The man moves first his left foot. Leading, his steps are left, right, left, right, right, left, while the following partner moves in this exact opposite step pattern on the other foot, in this case, the right foot.
The music has evolved over the years from 1940's jazz and big band to more contemporary interpretations and variations of the jazz and big bands of old. While dancers still dance to those old tunes, it's not unexpected to find Swing and Jitterbug-style Swing wherever the music is on the six-count, is upbeat, moves the couple to swing.