Rock music is a broad genre that encompasses many different styles. Two of the most popular rock music styles are Emo and ALT, both of which have three letters. Emo is a style of rock music that originated in the 1980s and is characterized by its emotional lyrics and melodic instrumentation. ALT, or alternative rock, is a style of rock music that emerged in the late 1980s and is characterized by its experimental sound and use of non-traditional instruments. Both styles of rock music have become popular among fans of the genre.