Source : Webster's Revised Unabridged Dictionary (1913)

Jar \Jar\, v. i. [imp. & p. p. {Jarred}; p. pr. & vb. n.
   {jarring}.] [Cf. OE. charken to creak, AS. cearcian to gnash,
   F. jars a gander, L. garrire to chatter, prate, OHG. kerran
   to chatter, croak, G. quarren to grumble, and E. jargon,
   ajar.]
   1. To give forth a rudely quivering or tremulous sound; to
      sound harshly or discordantly; as, the notes jarred on my
      ears.

            When such strings jar, what hope of harmony ?
                                                  --Shak.

            A string may jar in the best master's hand.
                                                  --Roscommon.

   2. To act in opposition or disagreement; to clash; to
      interfere; to quarrel; to dispute.

            When those renowned noble peers Greece Through
            stubborn pride among themselves did jar. --Spenser.

            For orders and degrees Jar not with liberty, but
            well consist.                         --Milton.

Jar \Jar\, n. [See {Ajar}.]
   A turn. [Only in phrase.]

   {On the jar}, on the turn, ajar, as a door.

Jar \Jar\, n. [F. jarre, Sp. jarra, from Ar. jarrah ewer; cf.
   Pers. jarrah.]
   1. A deep, broad-mouthed vessel of earthenware or glass, for
      holding fruit, preserves, etc., or for ornamental
      purposes; as, a jar of honey; a rose jar. --Dryden.

   2. The measure of what is contained in a jar; as, a jar of
      oil; a jar of preserves.

   {Bell jar}, {Leyden jar}. See in the Vocabulary.

Jar \Jar\, v. t.
   1. To cause a short, tremulous motion of, to cause to
      tremble, as by a sudden shock or blow; to shake; to shock;
      as, to jar the earth; to jar one's faith.

   2. To tick; to beat; to mark or tell off. [Obs.]

            My thoughts are minutes, and with sighs they jar
            Their watches on unto mine eyes.      --Shak.

Jar \Jar\, n.
   1. A rattling, tremulous vibration or shock; a shake; a harsh
      sound; a discord; as, the jar of a train; the jar of harsh
      sounds.

   2. Clash of interest or opinions; collision; discord; debate;
      slight disagreement.

            And yet his peace is but continual jar. --Spenser.

            Cease, cease these jars, and rest your minds in
            peace.                                --Shak.

   3. A regular vibration, as of a pendulum.

            I love thee not a jar of the clock.   --Shak.

   4. pl. In deep well boring, a device resembling two long
      chain links, for connecting a percussion drill to the rod
      or rope which works it, so that the drill is driven down
      by impact and is jerked loose when jammed.

Source : WordNet®

jar
     n 1: a vessel (usually cylindrical) with a wide mouth and without
          handles
     2: the quantity contained in a jar; "he drank a jar of beer"
        [syn: {jarful}]
     3: a sudden impact; "the door closed with a jolt" [syn: {jolt},
         {jounce}]
     [also: {jarring}, {jarred}]

jar
     v 1: be incompatible; be or come into conflict; "These colors
          clash" [syn: {clash}, {collide}]
     2: move or cause to move with a sudden jerky motion [syn: {jolt}]
     3: shock physically; "Georgia was shaken up in the Tech game"
        [syn: {shake up}, {bump around}]
     4: affect in a disagreeable way; "This play jarred the
        audience"
     5: place in a cylindrical vessel; "jar the jam"
     [also: {jarring}, {jarred}]

Source : Free On-Line Dictionary of Computing

jar
     
        {Java archive}