OC means "Original Content" or "Original Character." However, it generally means something that is originally or fully made by a person. Whether it is a sketch (drawing), story, or an idea that is not stolen or copied by anyone else. It is uniquely created by a person and it is known as their OC. For example - your friend is an artist and they make a sketch for you, hence this is the real OC or solely created by your friend.
