por·tal /ˈportḷ, ˈpɔr-/
 入口,大門(a.)門的
 por·tal /ˈpɔrtḷ/ 名詞
 (肝)門的
 Por·tal a. Anat. 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.
 Note: ☞ Portal is applied to other veins which break up into capillaries; as, the renal portal veins in the frog.
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 Por·tal n.
 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.   --Shak.
 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
      n 1: a grand and imposing entrance (often extended
           metaphorically); "the portals of the cathedral"; "the
           portals of heaven"; "the portals of success"
      2: a site that the owner positions as an entrance to other
         sites on the internet; "a portal typically has search
         engines and free email and chat rooms etc." [syn: portal
         site]
      3: a short vein that carries blood into the liver [syn: portal
         vein, hepatic portal vein, vena portae]