The Collaborative International Dictionary of English v.0.48:

Intention \In*ten"tion\, n. [F. intention, L. intentio. See
   Intend, and cf. Intension.]
   [1913 Webster]
   1. A stretching or bending of the mind toward an object;
      closeness of application; fixedness of attention;
      earnestness.
      [1913 Webster]

            Intention is when the mind, with great earnestness,
            and of choice, fixes its view on any idea. --Locke.
      [1913 Webster]

   2. A determination to act in a certain way or to do a certain
      thing; purpose; design; as, an intention to go to New
      York.
      [1913 Webster]

            Hell is paved with good intentions.   --Johnson.
      [1913 Webster]

   3. The object toward which the thoughts are directed; end;
      aim.
      [1913 Webster]

            In [chronical distempers], the principal intention
            is to restore the tone of the solid parts.
                                                  --Arbuthnot.
      [1913 Webster]

   4. The state of being strained. See Intension. [Obs.]
      [1913 Webster]

   5. (Logic) Any mental apprehension of an object.
      [1913 Webster]

   First intention (Logic), a conception of a thing formed by
      the first or direct application of the mind to the
      individual object; an idea or image; as, man, stone.

   Second intention (Logic), a conception generalized from
      first intuition or apprehension already formed by the
      mind; an abstract notion; especially, a classified notion,
      as species, genus, whiteness.

   To heal by the first intention (Surg.), to cicatrize, as a
      wound, without suppuration.

   To heal by the second intention (Surg.), to unite after
      suppuration.

   Syn: Design; purpose; object; aim; intent; drift; purport;
        meaning. See Design.
        [1913 Webster]

WordNet (r) 3.0 (2006):

intention
    n 1: an anticipated outcome that is intended or that guides your
         planned actions; "his intent was to provide a new
         translation"; "good intentions are not enough"; "it was
         created with the conscious aim of answering immediate
         needs"; "he made no secret of his designs" [syn: purpose,
         intent, intention, aim, design]
    2: (usually plural) the goal with respect to a marriage
       proposal; "his intentions are entirely honorable"
    3: an act of intending; a volition that you intend to carry out;
       "my intention changed once I saw her"

The Devil's Dictionary (1881-1906):

INTENTION, n.  The mind's sense of the prevalence of one set of
influences over another set; an effect whose cause is the imminence,
immediate or remote, of the performance of an involuntary act.