What is the meaning of the word "avant-garde"?

Definitions:

any creative group active in the innovation and application of new concepts and techniques in a given field (especially in the arts) noun
- Vera Wang's avant-garde fashion designs caught the attention and praise of the toughest critics.
New and unusual or experimental ideas, especially in the arts, or the people introducing them. NOUN
- At the avant-garde art show, we were shocked by some of the unusual sculptures.
Of or relating to an avant-garde. ADJECTIVE
- He was an enthusiast for the avant-garde.
radically new or original adjective
- An avant-garde theater piece.
The artists, writers, and musicians whose ideas, styles, and methods are very original or modern in comparison to the period in which they live or work. NOUN
- The photos are very avant-garde not the traditional portrait.