The cha-cha is a dance of Cuban origin, danced to the music of the same name introduced by Cuban composer and violinist Enrique Jorrin in the early 1950s. According to Wikipedia, this rhythm was developed from the danzón-mambo. The name of the dance is an onomatopoeia derived from the shuffling sound of the dancers’ feet. To make his music more appealing to dancers, Jorrín started composing songs where the melody was marked strongly on the first downbeat and the rhythm was less syncopated.
When Orquesta América performed these new compositions at the Silver Star Club in Havana, it was noticed that the dancers had improvised a triple step in their footwork producing the sound “cha-cha-cha”. Thus, the new style came to be known as “cha-cha-chá” and became associated with a dance where dancers perform a triple step. Cha-cha-chá is danced to authentic Cuban music, although in ballroom competitions it is often danced to Latin Pop or Latin Rock.