The Collaborative International Dictionary of English v.0.48:

Screech \Screech\ (skr[=e]ch), v. i. [imp. & p. p. Screeched;
   p. pr. & vb. n. Screeching.] [Also formerly, scritch, OE.
   skriken, skrichen, schriken, of Scand. origin; cf. Icel.
   skr[ae]kja to shriek, to screech, skr[imac]kja to titter, Sw.
   skrika to shriek, Dan. skrige; also Gael. sgreach, sgreuch,
   W. ysgrechio, Skr. kharj to creak. Cf. Shriek, v.,
   Scream, v.]
   To utter a harsh, shrill cry; to make a sharp outcry, as in
   terror or acute pain; to scream; to shriek. "The screech owl,
   screeching loud." --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Screech \Screech\, n.
   A harsh, shrill cry, as of one in acute pain or in fright; a
   shriek; a scream.
   [1913 Webster]

   Screech bird, or Screech thrush (Zool.), the fieldfare;
      -- so called from its harsh cry before rain.

   Screech rain.

   Screech hawk (Zool.), the European goatsucker; -- so called
      from its note. [Prov. Eng.]

   Screech owl. (Zool.)
   (a) A small American owl (Scops asio), either gray or
       reddish in color.
   (b) The European barn owl. The name is applied also to other
       species.
       [1913 Webster]

WordNet (r) 3.0 (2006):

screech
    n 1: a high-pitched noise resembling a human cry; "he ducked at
         the screechings of shells"; "he heard the scream of the
         brakes" [syn: screech, screeching, shriek,
         shrieking, scream, screaming]
    2: sharp piercing cry; "her screaming attracted the neighbors"
       [syn: scream, screaming, shriek, shrieking,
       screech, screeching]
    v 1: make a high-pitched, screeching noise; "The door creaked
         when I opened it slowly"; "My car engine makes a whining
         noise" [syn: whine, squeak, screech, creak,
         screak, skreak]
    2: utter a harsh abrupt scream [syn: squawk, screak,
       skreak, skreigh, screech]

Moby Thesaurus II by Grady Ward, 1.0:

111 Moby Thesaurus words for "screech":
   bark, battle cry, bawl, bay, bell, bellow, blare, blat, blate,
   bleat, blubber, boom, bray, breathe, buzz, cackle, call, caterwaul,
   chant, cheer, chirp, coo, creak, crow, cry, drawl, exclaim, flute,
   gasp, give tongue, give voice, groan, growl, grunt, hail, halloo,
   hiss, holler, hollo, hoot, howl, hurrah, keen, lilt, low, meow,
   mew, mewl, miaow, moan, moo, mumble, murmur, mutter, neigh, nicker,
   pant, penetrate, pierce, pipe, pule, rallying cry, roar, rumble,
   screak, scream, shout, shriek, shrill, sibilate, sigh, sing, skirl,
   skreigh, snap, snarl, snort, sob, sough, squall, squawk, squeak,
   squeal, thunder, troat, trumpet, twang, ululate, ululation, vent,
   voice, wail, war cry, war whoop, warble, whicker, whine, whinny,
   whisper, whistle, whoop, wrawl, yammer, yap, yawl, yawp, yell,
   yelp, yip, yo-ho, yowl