Slash is a term usually used in fanfiction communities to refer to homosexual relationships, generally between two men.

Slash is a common and popular genre in fanfiction. It usually concerns two male canon characters who fall in love with each other, even if these characters have heterosexual love interests in the canon, which can easily create an alternate universe. Slash is usually implausible -- if the characters were actually in a homosexual relationship in canon, the term wouldn't have to be used.

Fanfiction authors usually label their stories as slash in the summary to attract readers who enjoy these stories and warn off those who do not. Similarly, if a summary indicates that the story is about two men, an author will sometimes put "No slash!" in the summary.

Slash could also be used to refer to a published work about a homosexual relationship.