Ska ( /ˈskɑː/, Jamaican [skjæ]) is a music genre that originated in Jamaica in the late 1950s, and was the precursor to rocksteady and reggae.

Ska combined elements of Caribbean mento and calypso with American jazz and rhythm and blues. It is characterized by a walking bass line accented with rhythms on the upbeat. In the early 1960s, ska was the dominant music genre of Jamaica and was popular with British mods. Later it became popular with many skinheads.

Another explanation is that at a recording session in 1959 produced by Coxsone Dodd, double bassist Cluett Johnson instructed guitarist Ranglin to “play like ska, ska, ska”, although Ranglin has denied this, stating “Clue couldn’t tell me what to play!”

A further theory is that it derives from Johnson’s word skavoovie, with which he was known to greet his friends.[9] Jackie Mittoo insisted that the musicians themselves called the rhythm Staya Staya, and that it was Byron Lee who introduced the term ‘ska’.

Guitar and piano making a ska sound, like ‘ska, ska,’ that’s why we call it SKA. The sound of the guitar and the piano, that’s why we give it the name ska.
—Derrick Morga

As music changed in the United States, so did ska. In 1965 and 1966, when American soul music became slower and smoother, ska changed its sound accordingly and evolved into rocksteady.

However, rocksteady’s heyday was brief, peaking in 1967. By 1968, ska evolved again into reggae.

Article put together by Reggae united world wide team/taken from Wikipedia