Indie, short for independent, is a term often used to refer to independent music or artists who create music outside of the mainstream commercial music industry. Indie music is typically known for its alternative and nonconformist style, and is often associated with a DIY (Do-It-Yourself) approach in terms of production and distribution.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Nonmainstream, as music. Explanations are generated by AI and may be inaccurate.