资料来源 : Webster's Revised Unabridged Dictionary (1913)

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. --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.