portal, noun
Etymology: Middle English, from Middle French, from Medieval Latin portalecity gate, porch, from neuter of portalis of a gate, from Latin porta gate— more at PORT. Date:14th century
1: DOOR, ENTRANCE; especially: a grand or imposing one
2: the whole architectural composition surrounding and including the doorways and porches of a church
3: the approach or entrance to a bridge or tunnel
4: a communicating part or area of an organism; specifically: the point at which something (as a pathogen) enters the body

portal, adjective
Etymology: New Latin porta transverse fissure of the liver, from Latin, gate. Date:1845
1: of or relating to the transverse fissure on the underside of the liver where most of the vessels enter
2: of, relating to, or being a portal vein

portal system, noun
Etymology: portal vein. Date:1851
: a system of veins that begins and ends in capillaries

portal vein, noun
Etymology: portal. Date:1845
: a vein that collects blood from one part of the body and distributes it in another through capillaries;
especially : a vein carrying blood from the digestive organs and spleen to the liver

portal \Por"tal\, n. [OF. portal, F. portail, LL. portale, fr. L. porta a gate. See Port a gate.]
1. A door or gate; hence, a way of entrance or exit, especially one that is grand and imposing.
"Thick with sparkling orient gems The portal shone." — Milton
"From out the fiery portal of the east." — Shakespeare
2. (Arch.) (a) The lesser gate, where there are two of different dimensions.
(b) Formerly, a small square corner in a room separated from the rest of the apartment by wainscoting, forming a short passage to another apartment.
(c) By analogy with the French portail, used by recent writers for the whole architectural composition which surrounds and includes the doorways and porches of a church.
3. (Bridge Building) The space, at one end, between opposite trusses when these are terminated by inclined braces.
4. A prayer book or breviary; a portass. [Obs.]
Portal bracing (Bridge Building), a combination of struts and ties which lie in the plane of the inclined braces at a portal, serving to transfer wind pressure from the upper parts of the trusses to an abutment or pier of the bridge.

portal \Por"tal\, a. (Anatomy)
Of or pertaining to a porta, especially the porta of the liver; as, the portal vein, which enters the liver at the porta, and divides into capillaries after the manner of an artery.

portal n: an grand and imposing entrance (often extended metaphorically);
"the portals of the cathedral"; "the portals of heaven"; "the portals of success"

portal— A door or gate, usually of importance or large in size. In most Gothic cathedrals there were three portals in the main facade.

portal n: entrance, entry, entryway, entreé, inlet, ingress;
access, opening, adit; door, doorway, gate, gateway, wicket, postern.

portal: Process-Oriented Real-Time Algorithmic Language
["PORTAL— A Pascal-based Real-Time Programming Language",
R. Schild in Algorithmic Languages, J.W. deBakker et al eds, N-H 1981]

Portal, AZ, Zip code: 85632
Portal, GA, Zip code: 30450, Location: 32.53627 N, 81.93058 W, Population (1990): 522
Portal, ND, Zip code: 58772, Location: 48.99561 N, 102.54787 W, Population (1990): 192