Copyright infringement is the use of works protected by copyright law without permission, infringing certain exclusive rights granted to the copyright holder, such as the right to reproduce, distribute, display or perform the protected work, or to make derivative works. The copyright holder is typically the work's creator, or a publisher or other business to whom copyright has been assigned. Copyright holders routinely invoke legal and technological measures to prevent and penalize copyright infringement.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): You wrote a song that was based on an original work, what is this called?
derivative works