The Collaborative International Dictionary of English v.0.48:

Resolution \Res`o*lu"tion\ (-l?"sh?n), n. [F. r['e]solution. L.
   resolutio a loosening, solution. See Resolve.]
   1. The act, operation, or process of resolving. Specifically:
      (a) The act of separating a compound into its elements or
          component parts.
      (b) The act of analyzing a complex notion, or solving a
          vexed question or difficult problem.
          [1913 Webster]

                The unraveling and resolution of the
                difficulties that are met with in the execution
                of the design are the end of an action.
                                                  --Dryden.
          [1913 Webster]

   2. The state of being relaxed; relaxation. [Obs.]
      [1913 Webster]

   3. The state of being resolved, settled, or determined;
      firmness; steadiness; constancy; determination.
      [1913 Webster]

            Be it with resolution then to fight.  --Shak.
      [1913 Webster]

   4. That which is resolved or determined; a settled purpose;
      determination. Specifically: A formal expression of the
      opinion or will of an official body or a public assembly,
      adopted by vote; as, a legislative resolution; the
      resolutions of a public meeting.
      [1913 Webster]

   5. The state of being resolved or firm in opinion or thought;
      conviction; assurance. [Obs.]
      [1913 Webster]

            Little resolution and certainty there is as touching
            the islands of Mauritania.            --Holland.
      [1913 Webster]

   6. (Math.) The act or process of solving; solution; as, the
      resolution of an equation or problem.
      [1913 Webster]

   7. (Med.) A breaking up, disappearance; or termination, as of
      a fever, a tumor, or the like.
      [1913 Webster]

   8. (Mus.) The passing of a dissonant into a consonant chord
      by the rising or falling of the note which makes the
      discord.
      [1913 Webster]

   9. (Technical) The act of distinguishing between two close
      but not identical objects, or, when taking a measurement,
      bbetween two close values of the property measured.
      [PJC]

   10. (Technical) a measure of the ability to distinguish
       between two close but not identical values of the
       property being measured; it is expressed as the
       difference in values of a property necessary to make such
       a distinction; as, a microscope with a resolution of one
       micron; a thermometer with a resolution of one-tenth of a
       degree. Also called resolving power.
       [PJC]

   Joint resolution. See under Joint, a.

   Resolution of a force or Resolution of a motion (Mech.),
      the separation of a single force or motion into two or
      more which have different directions, and, taken together,
      are an equivalent for the single one; -- the opposite of
      composition of a force.

   Resolution of a nebula (Astron.), the exhibition of it to
      the eye by a telescope of such power as to show it to be
      composed of small stars.
      [1913 Webster]

   Syn: Decision; analysis; separation; disentanglement;
        dissolution; resolvedness; resoluteness; firmness;
        constancy; perseverance; steadfastness; fortitude;
        boldness; purpose; resolve. See Decision.
        [1913 Webster]

WordNet (r) 3.0 (2006):

resolving power
    n 1: the ability of a microscope or telescope to measure the
         angular separation of images that are close together [syn:
         resolving power, resolution]