Short answers, pulled from the story.
Pop art is an art movement that emerged in the United Kingdom and the United States during the mid to late 1950s. It challenged fine art traditions by including imagery from popular and mass culture, such as advertising, comic strips, product packaging, and celebrities, into painting, sculpture, and printmaking.
The origin of the term is contested. According to the son of John McHale, his father coined it in 1954 in conversation with Frank Cordell, while other sources credit British critic Lawrence Alloway. Both versions agree it was used in Independent Group discussions by mid-1955, and it first appeared in print in the 1956 article "But Today We Collect Ads" by Alison and Peter Smithson.
Andy Warhol was called the "innovator of pop art" by The Observer in 1964 and is widely regarded as the central figure of the movement. He pushed pop beyond a visual style into a cultural phenomenon through his Factory studio, his silkscreen portraits of figures like Marilyn Monroe and Elvis Presley, and works such as his Campbell's Tomato Juice Box.
British pop art was more academic and viewed American popular culture from a distance, giving it romantic, sentimental, and humorous overtones. American pop art emerged as a reaction returning to hard-edged, representational art, and because American artists faced mass-produced imagery daily, their work was generally more bold and aggressive.
The Independent Group, founded in London in 1952, is regarded as the precursor to the pop art movement. It gathered young painters, sculptors, architects, writers, and critics whose discussions centered on mass advertising, movies, product design, comic strips, science fiction, and technology.
Pop art spread internationally through related and parallel movements, including Nouveau réalisme founded in France in 1960 by Pierre Restany and Yves Klein, El Equipo Crónica in Spain, and Japanese figures like Yayoi Kusama and Tadanori Yokoo. It later flourished in New Zealand through Kiwiana since the 1990s and appeared in Russia as Sots Art in the 1970s.