[quote=@Strange Rodent]
Open sandwiches are melts/toast, not sandwiches. The two pieces of bread are not on the same axis. Hot dogs are tacos in structure. Three contiguous sides of cooked, solid, meal based foodstuff with filling in.
[/quote]

[quote=Wikipedia]An open sandwich, also known as an open-face/open-faced sandwich, bread baser, bread platter[1] or tartine,[2] consists of one or more slices of bread with one or more food items on top.[/quote]

Well, it meets [@Fabricant451]'s definition to a degree.