资料来源 : pyDict

虚拟虚的,实质的,有效的,事实上的

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

Virtual \Vir"tu*al\ (?; 135), a. [Cf. F. virtuel. See {Virtue}.]
   1. Having the power of acting or of invisible efficacy
      without the agency of the material or sensible part;
      potential; energizing.

            Heat and cold have a virtual transition, without
            communication of substance.           --Bacon.

            Every kind that lives, Fomented by his virtual
            power, and warmed.                    --Milton.

   2. Being in essence or effect, not in fact; as, the virtual
      presence of a man in his agent or substitute.

            A thing has a virtual existence when it has all the
            conditions necessary to its actual existence.
                                                  --Fleming.

            To mask by slight differences in the manners a
            virtual identity in the substance.    --De Quincey.

   {Principle of virtual velocities} (Mech.), the law that when
      several forces are in equilibrium, the algebraic sum of
      their virtual moments is equal to zero.

   {Virtual focus} (Opt.), the point from which rays, having
      been rendered divergent by reflection of refraction,
      appear to issue; the point at which converging rays would
      meet if not reflected or refracted before they reach it.
      

   {Virtual image}. (Optics) See under {Image}.

   {Virtual moment} (of a force) (Mech.), the product of the
      intensity of the force multiplied by the virtual velocity
      of its point of application; -- sometimes called {virtual
      work}.

   {Virtual velocity} (Mech.), a minute hypothetical
      displacement, assumed in analysis to facilitate the
      investigation of statical problems. With respect to any
      given force of a number of forces holding a material
      system in equilibrium, it is the projection, upon the
      direction of the force, of a line joining its point of
      application with a new position of that point indefinitely
      near to the first, to which the point is conceived to have
      been moved, without disturbing the equilibrium of the
      system, or the connections of its parts with each other.
      Strictly speaking, it is not a velocity but a length.

   {Virtual work}. (Mech.) See {Virtual moment}, above.

资料来源 : WordNet®

virtual
     adj 1: being actually such in almost every respect; "a practical
            failure"; "the once elegant temple lay in virtual
            ruin" [syn: {virtual(a)}, {practical(a)}]
     2: being such in essence or effect though not in actual fact;
        "a virtual dependence on charity"; "a virtual revolution";
        "virtual reality" [syn: {virtual(a)}]

资料来源 : Free On-Line Dictionary of Computing

virtual
     
         (Via the technical term {virtual
        memory}, probably from the term "virtual image" in optics)
        1. Common alternative to {logical}; often used to refer to the
        artificial objects (like addressable {virtual memory} larger
        than physical memory) created by a computer system to help the
        system control access to shared resources.
     
        2. Simulated; performing the functions of something that isn't
        really there.  An imaginative child's doll may be a virtual
        playmate.
     
        Opposite of {real} or physical.
     
        [{Jargon File}]
     
        (1994-11-30)