[1] : The Collaborative International Dictionary of English v.0.48

yowl \yowl\, v. i. see yawl, v. i.
   to utter a loud, long, and mournful cry, as a dog; to howl;
   to yell.
   1913 webster
see also:
yawl 

[2] : The Collaborative International Dictionary of English v.0.48

yowl \yowl\, n.
   a loud, protracted, and mournful cry, as that of a dog; a
   howl.
   1913 webster

[3] : WordNet (r) 2.0

yowl
     n : a very loud utterance like the sound of an animal; "his
         bellow filled the hallway" syn: bellow, bellowing, holla,
          holler, hollering, hollo, holloa, roar, roaring
     v 1: cry loudly, as of animals; "the coyotes were howling in the
          desert" syn: howl, wrawl, yammer
     2: utter shrieks, as of cats syn: caterwaul
see also:
bellow bellowing holla holler hollering hollo 
holloa roar roaring howl wrawl 
yammer caterwaul 

[4] : Moby Thesaurus II by Grady Ward, 1.0

79 moby thesaurus words for "yowl":
   bark, battle cry, bawl, bay, bell, bellow, blare, blat, blate,
   bleat, bray, call, caterwaul, cheer, cry, cry out, dolorous tirade,
   give tongue, give voice, groan, hail, halloo, holler, hollo, hoot,
   howl, hurrah, jeremiad, keen, lament, low, make an outcry, meow,
   mew, mewl, miaow, moan, moo, murmur, mutter, neigh, nicker, outcry,
   plaint, planctus, pule, rallying cry, roar, screak, scream,
   screech, shout, shriek, sob, squall, squawk, squeak, squeal,
   tirade, troat, ululate, ululation, wail, wail of woe, war cry,
   war whoop, whicker, whimper, whine, whinny, whoop, yammer, yap,
   yawl, yawp, yell, yelp, yip, yo-ho

Yowl >> Y Words
Yowl, definition of term: Yowl
yowl_pag1.html