- The main entrance to a building or house, normally fronts onto a street
- (computing) The normal portal page to a website.
- (baseball) The path of a pitch which starts inside and then slides over the plate.
- His front door slider is hard to handle.
- (slang) vagina, as a means of sexual intercourse, contrasted with the anus or "back door"
(main entrance to a building): foredoor