Source : Webster's Revised Unabridged Dictionary (1913)

Pain \Pain\, n. [OE. peine, F. peine, fr. L. poena, penalty,
   punishment, torment, pain; akin to Gr. ? penalty. Cf.
   {Penal}, {Pine} to languish, {Punish}.]
   1. Punishment suffered or denounced; suffering or evil
      inflicted as a punishment for crime, or connected with the
      commission of a crime; penalty. --Chaucer.

            We will, by way of mulct or pain, lay it upon him.
                                                  --Bacon.

            Interpose, on pain of my displeasure. --Dryden.

            None shall presume to fly, under pain of death.
                                                  --Addison.

   2. Any uneasy sensation in animal bodies, from slight
      uneasiness to extreme distress or torture, proceeding from
      a derangement of functions, disease, or injury by
      violence; bodily distress; bodily suffering; an ache; a
      smart. ``The pain of Jesus Christ.'' --Chaucer.

   Note: Pain may occur in any part of the body where sensory
         nerves are distributed, and it is always due to some
         kind of stimulation of them. The sensation is generally
         referred to the peripheral end of the nerve.

   3. pl. Specifically, the throes or travail of childbirth.

            She bowed herself and travailed, for her pains came
            upon her.                             --1 Sam. iv.
                                                  19.

   4. Uneasiness of mind; mental distress; disquietude; anxiety;
      grief; solicitude; anguish. --Chaucer.

            In rapture as in pain.                --Keble.

   5. See {Pains}, labor, effort.

   {Bill of pains and penalties}. See under {Bill}.

   {To die in the pain}, to be tortured to death. [Obs.]
      --Chaucer.

Pain \Pain\, v. t. [imp. & p. p. {Pained}; p. pr. & vb. n.
   {Paining}.] [OE. peinen, OF. pener, F. peiner to fatigue. See
   {Pain}, n.]
   1. To inflict suffering upon as a penalty; to punish. [Obs.]
      --Wyclif (Acts xxii. 5).

   2. To put to bodily uneasiness or anguish; to afflict with
      uneasy sensations of any degree of intensity; to torment;
      to torture; as, his dinner or his wound pained him; his
      stomach pained him.

            Excess of cold, as well as heat, pains us. --Locke
      .

   3. To render uneasy in mind; to disquiet; to distress; to
      grieve; as a child's faults pain his parents.

            I am pained at my very heart.         --Jer. iv. 19.

   {To pain one's self}, to exert or trouble one's self; to take
      pains; to be solicitous. [Obs.] ``She pained her to do all
      that she might.'' --Chaucer.

   Syn: To disquiet; trouble; afflict; grieve; aggrieve;
        distress; agonize; torment; torture.

Source : WordNet®

pain
     n 1: a symptom of some physical hurt or disorder; "the patient
          developed severe pain and distension" [syn: {hurting}]
     2: emotional distress; a fundamental feeling that people try to
        avoid; "the pain of loneliness" [syn: {painfulness}] [ant:
         {pleasure}]
     3: a somatic sensation of acute discomfort; "as the intensity
        increased the sensation changed from tickle to pain" [syn:
         {painful sensation}]
     4: a bothersome annoying person; "that kid is a terrible pain"
        [syn: {pain in the neck}, {nuisance}]
     5: something or someone that causes trouble; a source of
        unhappiness; "washing dishes was a nuisance before we got
        a dish washer"; "a bit of a bother"; "he's not a friend,
        he's an infliction" [syn: {annoyance}, {bother}, {botheration},
         {infliction}, {pain in the neck}, {pain in the ass}]

pain
     v 1: cause bodily suffering to [syn: {afflict}, {trouble}, {ail}]
     2: cause emotional anguish or make miserable; "It pains me to
        see my children not being taught well in school" [syn: {anguish},
         {hurt}]