Final answer:
Avant-garde in twentieth-century music and art involved artists and musicians breaking away from traditional styles and techniques to create innovative and unconventional forms of art.
Step-by-step explanation:
Avant-garde refers to a group of artists in the twentieth century who challenged traditional artistic styles and techniques. They aimed to break away from conservative academic traditions and create new, innovative forms of art.
In music, avant-garde composers and musicians explored unconventional scales, notes, and tempos, pushing the boundaries of what was considered acceptable.
The avant-garde movement was not limited to any specific political ideology, although some artists were associated with political activism.