The Collaborative International Dictionary of English v.0.48:

Think \Think\, v. t. [imp. & p. p. Thought; p. pr. & vb. n.
   Thinking.] [OE. thinken, properly, to seem, from AS.
   [thorn]yncean (cf. Methinks), but confounded with OE.
   thenken to think, fr. AS. [thorn]encean (imp.
   [thorn][=o]hte); akin to D. denken, dunken, OS. thenkian,
   thunkian, G. denken, d["u]nken, Icel. [thorn]ekkja to
   perceive, to know, [thorn]ykkja to seem, Goth. [thorn]agkjan,
   [thorn]aggkjan, to think, [thorn]ygkjan to think, to seem,
   OL. tongere to know. Cf. Thank, Thought.]
   1. To seem or appear; -- used chiefly in the expressions
      methinketh or methinks, and methought.
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   Note: These are genuine Anglo-Saxon expressions, equivalent
         to it seems to me, it seemed to me. In these
         expressions me is in the dative case.
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   2. To employ any of the intellectual powers except that of
      simple perception through the senses; to exercise the
      higher intellectual faculties.
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            For that I am
            I know, because I think.              --Dryden.
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   3. Specifically:
      (a) To call anything to mind; to remember; as, I would
          have sent the books, but I did not think of it.
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                Well thought upon; I have it here. --Shak.
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      (b) To reflect upon any subject; to muse; to meditate; to
          ponder; to consider; to deliberate.
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                And when he thought thereon, he wept. --Mark
                                                  xiv. 72.
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                He thought within himself, saying, What shall I
                do, because I have no room where to bestow my
                fruits?                           --Luke xii.
                                                  17.
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      (c) To form an opinion by reasoning; to judge; to
          conclude; to believe; as, I think it will rain
          to-morrow.
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                Let them marry to whom they think best. --Num.
                                                  xxxvi. 6.
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      (d) To purpose; to intend; to design; to mean.
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                I thought to promote thee unto great honor.
                                                  --Num. xxiv.
                                                  11.
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                Thou thought'st to help me.       --Shak.
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      (e) To presume; to venture.
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                Think not to say within yourselves, We have
                Abraham to our father.            --Matt. iii.
                                                  9.
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   Note: To think, in a philosophical use as yet somewhat
         limited, designates the higher intellectual acts, the
         acts preeminently rational; to judge; to compare; to
         reason. Thinking is employed by Hamilton as
         "comprehending all our collective energies." It is
         defined by Mansel as "the act of knowing or judging by
         means of concepts,"by Lotze as "the reaction of the
         mind on the material supplied by external influences."
         See Thought.
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   To think better of. See under Better.

   To think much of, or To think well of, to hold in esteem;
      to esteem highly.
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   Syn: To expect; guess; cogitate; reflect; ponder;
        contemplate; meditate; muse; imagine; suppose; believe.
        See Expect, Guess.
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The Collaborative International Dictionary of English v.0.48:

Thought \Thought\,
   imp. & p. p. of Think.
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The Collaborative International Dictionary of English v.0.48:

Thought \Thought\, n. [OE. [thorn]oght, [thorn]ouht, AS.
   [thorn][=o]ht, ge[thorn][=o]ht, fr. [thorn]encean to think;
   akin to D. gedachte thought, MHG. d[=a]ht, ged[=a]ht, Icel.
   [thorn][=o]ttr, [thorn][=o]tti. See Think.]
   1. The act of thinking; the exercise of the mind in any of
      its higher forms; reflection; cogitation.
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            Thought can not be superadded to matter, so as in
            any sense to render it true that matter can become
            cogitative.                           --Dr. T.
                                                  Dwight.
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   2. Meditation; serious consideration.
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            Pride, of all others the most dangerous fault,
            Proceeds from want of sense or want of thought.
                                                  --Roscommon.
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   3. That which is thought; an idea; a mental conception,
      whether an opinion, judgment, fancy, purpose, or
      intention.
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            Thus Bethel spoke, who always speaks his thought.
                                                  --Pope.
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            Why do you keep alone, . . .
            Using those thoughts which should indeed have died
            With them they think on?              --Shak.
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            Thoughts come crowding in so fast upon me, that my
            only difficulty is to choose or to reject. --Dryden.
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            All their thoughts are against me for evil. --Ps.
                                                  lvi. 5.
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   4. Solicitude; anxious care; concern.
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            Hawis was put in trouble, and died with thought and
            anguish before his business came to an end. --Bacon.
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            Take no thought for your life, what ye shall eat, or
            what ye shall drink.                  --Matt. vi.
                                                  25.
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   5. A small degree or quantity; a trifle; as, a thought
      longer; a thought better. [Colloq.]
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            If the hair were a thought browner.   --Shak.
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   Note: Thought, in philosophical usage now somewhat current,
         denotes the capacity for, or the exercise of, the very
         highest intellectual functions, especially those
         usually comprehended under judgment.
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               This [faculty], to which I gave the name of the
               "elaborative faculty," -- the faculty of
               relations or comparison, -- constitutes what is
               properly denominated thought.      --Sir W.
                                                  Hamilton.
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   Syn: Idea; conception; imagination; fancy; conceit; notion;
        supposition; reflection; consideration; meditation;
        contemplation; cogitation; deliberation.
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WordNet (r) 3.0 (2006):

thought
    n 1: the content of cognition; the main thing you are thinking
         about; "it was not a good idea"; "the thought never entered
         my mind" [syn: idea, thought]
    2: the process of using your mind to consider something
       carefully; "thinking always made him frown"; "she paused for
       thought" [syn: thinking, thought, thought process,
       cerebration, intellection, mentation]
    3: the organized beliefs of a period or group or individual;
       "19th century thought"; "Darwinian thought"
    4: a personal belief or judgment that is not founded on proof or
       certainty; "my opinion differs from yours"; "I am not of your
       persuasion"; "what are your thoughts on Haiti?" [syn:
       opinion, sentiment, persuasion, view, thought]

Moby Thesaurus II by Grady Ward, 1.0:

306 Moby Thesaurus words for "thought":
   Parthian shot, accommodatingness, address, admonition, advertence,
   advertency, advice, advising, advocacy, affirmation, agreeableness,
   alertness, allegation, answer, antelope, anticipation, apostrophe,
   apprehension, arrow, assertion, assiduity, assiduousness,
   association, association of ideas, assumption, attention,
   attention span, attentiveness, attitude, averment, awareness, bit,
   blue darter, blue streak, brainstorm, brainwork, briefing,
   brooding, brown study, cannonball, care, cast, caution, caveat,
   cerebration, certainty, chain of thought, climate of opinion,
   cogitation, cogitative, cognitive, comment, common belief,
   community sentiment, compassion, complaisance, conceit,
   concentrating, concentration, concentrative, concept, conception,
   conceptive, conceptual, conceptualized, concern, conclusion,
   confidence, consciousness, consensus gentium, considerateness,
   consideration, considering, consultation, contemplating,
   contemplation, contemplative, council, counsel, courser, crack,
   current of thought, dart, dash, declaration, deliberating,
   deliberation, deliberative, delicacy, design, dictum, diligence,
   direction, dream, eagle, ear, earnestness, electricity, estimate,
   estimation, ethos, exclamation, excogitating, exhortation,
   expectancy, expectation, expostulation, express train, expression,
   eye, fancy, feeling, flash, flow of thought, gazelle,
   general belief, gleam, greased lightning, greeting, greyhound,
   guidance, hare, heed, heedfulness, helpfulness, hint, hope,
   hortation, idea, ideative, image, imago, imminence, impression,
   indulgence, infusion, inkling, inmost thoughts, instruction,
   intellect, intellection, intellectual object, intelligence,
   intention, intentiveness, intentness, interjection, intimation,
   introspective, jet plane, judgment, kindliness, kindness, leniency,
   lick, light, lightning, lights, little, look, meditating,
   meditation, meditative, memories, memory, memory-trace, mental,
   mental image, mental impression, mentation, mention, mercury, mind,
   mindfulness, monition, museful, musing, mystique, noetic, note,
   notice, notion, obligingness, observance, observation, opinion,
   parley, pensive, perception, personal judgment, phrase, plan,
   planning, point of view, pondering, popular belief, position,
   posture, prehensive, presumption, prevailing belief, probability,
   pronouncement, proposal, prospect, public belief, public opinion,
   question, quicksilver, ratiocination, rationality, reaction,
   reason, reasoning, recept, recommendation, reflecting, reflection,
   reflective, regard, regardfulness, reliance, remark, remembrances,
   remonstrance, representation, respect, rocket, ruminant,
   ruminating, rumination, ruminative, sauce, say, saying,
   scared rabbit, scheme, scintilla, seasoning, secret thoughts,
   sentence, sentiment, serious, shade, shadow, shot, sight, sip,
   smack, small amount, smattering, smell, sober, solicitousness,
   solicitude, soupcon, spark, speculation, speculative, spice,
   sprinkling, stance, statement, streak, streak of lightning,
   stream of consciousness, striped snake, subjoinder, suggestion,
   sup, supposition, suspicion, swallow, sympathy, tact, tactfulness,
   taint, taste, tempering, tenderness, theory, thinking, thoughtful,
   thoughtfulness, thoughts, thunderbolt, tinct, tincture, tinge,
   tint, toleration, torrent, touch, trace, train of thought, trifle,
   unastonishment, utterance, vestige, view, vision, warning,
   way of thinking, wind, wistful, word



Bouvier's Law Dictionary, Revised 6th Ed (1856):

THOUGHT. The operation of the mind. No one can be punished for his mere
thoughts however wicked they may be. Human laws cannot reach them, first,
because they are unknown; and, secondly, unless made manifest by some
action, they are not injurious to any one; but when they manifest
themselves, then the act, which is the consequence, may be punished. Dig. 50
16, 225.