OC = Original Character

Refers to a non-canon character created by the author that is featured prominently in the story. May be male or female, and either a major or minor character in comparison to the canon characters. May or may not be a Mary-Sue.

OFC = Original Female Character

Refers to a female character created by the author that is featured prominently in the story. May or may not be a Mary-Sue.

OMC = Original Male Character

Refers to a male character created by the author that is featured prominently in the story. May or may not be a Gary-Stu.