Landscapes, seascapes, and cityscapes are just what you would think: outdoor shots of wide expanses of land, sea, or city buildings.
“Scapes” are frequently, but not always, horizontal in format. Many land and sea scapes will be nature oriented, but the nature requirements like “no hand of man” do not apply. A picture of a single building, plant, or ship would not be a “scape”, but pretty much any wide outdoor shot will qualify.