Rockers (also known as leather boys or ton-up boys) are members of a biker subculture that originated in the United Kingdom during the late 1950s and was popular in the 1960s. It was mainly centred on motorcycles and rock 'n' roll music. By 1965, the term greaser had also been introduced to Great Britain and, since then, the terms greaser and rocker have become synonymous within the British Isles, although used differently in North America and elsewhere.