Improvisational music, also known as free-form or spontaneous music, is a genre of music that is characterized by the improvisation of melodies, harmonies, rhythms, and other musical elements. Synonyms for improvisational music include experimental music, avant-garde music, free jazz, free improvisation, and improvisational ensemble. Experimental music refers to the exploration of new musical forms, techniques, and materials. Avant-garde music refers to the vanguard of a particular artistic movement, pushing the boundaries of what is considered mainstream. Free jazz is a subgenre of jazz that emphasizes improvisation, while free improvisation is a broader term that encompasses all forms of improvised music. Improvisational ensemble refers to a group of musicians who perform without a preconceived plan or structure.