Orphan works are works for which there is no clear copyright owner. Orphan works are protected under copyright law, as are all intellectual and creative works, but because of the lack of obvious ownership, it can be almost impossible to obtain copyright permission for orphan works.
If you have decided you need permission from a rights holder to use a copyrighted work, but can't locate any way to contact them, or never heard back from them after you contacted them, you might be dealing with an orphan work.
Unfortunately, a work's status as an orphan work does not allow you to treat the work any differently than any other work.
If you are in this situation, you must either,