The Collaborative International Dictionary of English v.0.48:

Parch \Parch\ (p[aum]rch), v. t. [imp. & p. p. Parched; p. pr.
   & vb. n. Parching.] [OE. perchen to pierce, hence used of a
   piercing heat or cold, OF. perchier, another form of percier,
   F. percer. See Pierce.]
   1. To burn the surface of; to scorch; to roast over the fire,
      as dry grain; as, to parch the skin; to parch corn.
      [1913 Webster]

            Ye shall eat neither bread, nor parched corn. --Lev.
                                                  xxiii. 14.
      [1913 Webster]

   2. To dry to extremity; to shrivel with heat; as, the mouth
      is parched from fever.
      [1913 Webster]

            The ground below is parched.          --Dryden.
      [1913 Webster]

WordNet (r) 3.0 (2006):

parched
    adj 1: dried out by heat or excessive exposure to sunlight; "a
           vast desert all adust"; "land lying baked in the heat";
           "parched soil"; "the earth was scorched and bare";
           "sunbaked salt flats" [syn: adust, baked, parched,
           scorched, sunbaked]
    2: toasted or roasted slightly; "parched corn was a staple of
       the Indian diet"

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "parched":
   Sanforized, adust, ashen, ashy, athirst, attenuated, baked,
   blistered, burned, burnt, burnt-up, consumed, consumed by fire,
   corky, dehydrated, desiccated, dried, dried-up, droughty, dry,
   emacerated, emaciated, evaporated, exsiccated, gutted, incinerated,
   mummified, preshrunk, pyrographic, pyrolyzed, scorched, sear,
   seared, sere, shriveled, shriveled up, shrunk, shrunken, singed,
   sun-dried, sunbaked, sunburned, thin, thirsting, thirsty, wasted,
   wasted away, weazened, wind-dried, withered, wizen, wizen-faced,
   wizened