 The phrase "rocking and rolling" originally described the movement of a ship on the ocean, but by the early 20th century was used both to describe the spiritual fervor of black church rituals and as a sexual analogy.Various gospel, blues and swing recordings used the phrase before it became used more frequently – but still intermittently – in the 1940s, on recordings and in reviews of what became known as "rhythm and blues" music aimed at a black audience.In 1934, the song "Rock and Roll" by the Boswell Sisters appeared in the film "Transatlantic Merry-Go-Round".