Portal often refers to: Portal (architecture), an opening in a wall of a building, gate or fortification, or the extremities (ends) of a tunnel. Portal may also refer to: Arts and entertainment. Gaming. Portal (series), a series of video games developed by Valve. Portal (video game), a 2007 video game, the first in the series. Portal 2, the 2011 sequel. Portal Stories: Mel, a mod for Portal 2. Portal Revolution, a mod for Portal 2. Portal Reloaded, a mod for Portal 2. Aperture Tag, a mod for Portal 2. Portal (1986 video game), a 1986 computer game by Activision.
https://en.wikipedia.org/wiki/Portal