John Travolta's First Hit   John Travolta first gained fame as Vinnie Barbarino on the television series Welcome Back, Kotter (1975).
popular adjective (LIKED) A2 liked, enjoyed, or supported by many people: She's the most popular teacher in school. That song was popular with people from my father's generation. Walking is a popular form of exercise in Britain.
Pop is short for popular, and it's remained the defining term for the ever-changing music favoured by the public. Although not specifically applied until the middle of the 20th century, pop music as such can be traced by a few decades before that.