prog rock
From Longman Dictionary of Contemporary Englishprog rockprog rock /ˈprɒɡ rɒk $ ˈprɑːg rɑːk/ (also progressive rock) noun [uncountable] a type of rock music that was produced especially in the 1970s. Prog rock albums typically have an impressive sound involving electronic keyboards or orchestral instruments, and are often based on a particular idea or story