Bop

Bop usually refers to genres of music, for example:
• Bop, shortened form of Bebop, an early modern jazz developed in the 1940s.
• Hard Bop, a style of jazz music that is an extension of bebop or "bop" music.
• Bop also refers to a derivative style of Chicago drill, known for its heavier focus on melodic vocal deliveries and the use of upbeat synths in the beats.

More recently, in pop music (k-pop especially), to declare that something is 'a bop' is to express that it's a really good song; similar to calling something ‘a tune' or ‘your jam'.