Source : Webster's Revised Unabridged Dictionary (1913)

Tart \Tart\, n. [OE. tarte, F. tarte; perhaps originally the
   same word as tourte, LL. torta, fr. L. tortus, p. p. of
   torquere to twist, bend, wind, because tarts were originally
   made of a twisted shape. Cf. {Torture}, n.]
   A species of small open pie, or piece of pastry, containing
   jelly or conserve; a sort of fruit pie.

Tart \Tart\, a. [AS. teart. [root]63. Cf. {Tear}, v. t.]
   1. Sharp to the taste; acid; sour; as, a tart apple.

   2. Fig.: Sharp; keen; severe; as, a tart reply; tart
      language; a tart rebuke.

            Why art thou tart, my brother?        --Bunyan.

Source : WordNet®

tart
     adj 1: tasting sour like a lemon [syn: {lemony}, {lemonlike}, {sourish},
             {tangy}]
     2: harsh; "sharp criticism"; "a sharp-worded exchange"; "a tart
        remark" [syn: {sharp}, {sharp-worded}]

tart
     n 1: a woman who engages in sexual intercourse for money [syn: {prostitute},
           {cocotte}, {whore}, {harlot}, {bawd}, {cyprian}, {fancy
          woman}, {working girl}, {sporting lady}, {lady of
          pleasure}, {woman of the street}]
     2: a small open pie with a fruit filling
     3: pastry cup with a filling of fruit or custard and no top
        crust