what does canon mean?

Canon is something that has occurred in a series, contrary to non-canon, where something is simply made up. I think Femslash, means a lesbian relationship, or simply just lesbian sex. I might be wrong.

Canon means something that is showed to be a fact in a fandom. Like Spider-man dating and/or marrying Mary Jane Watson is canon.

Spider-man dating Black Widow would be fanon. As in a ship formed por the fãs and it would stay fanon unless the creators actually allow Spidey to encontro, data Black Widow.

slash is virtually a pairing (couple that fãs create) but slash is normally used in conjunction with "slash pairing" Normally if I remember correctly it could be male x male or hetero pairing. And femslash is for female x female pairing.

Before you ask or anyone else no I don't consider myself a shipper. I am friends with a bunch of them. And while I do like some pairings. I am not crazy for them por any means.