Source : Webster's Revised Unabridged Dictionary (1913)

Howl \Howl\, v. i. [imp. & p. p. {Howled}; p. pr. & vb. n.
   {Howling}.] [OE. houlen, hulen; akin to D. huilen, MHG.
   hiulen, hiuweln, OHG. hiuwil[=o]n to exult, h?wo owl, Dan.
   hyle to howl.]
   1. To utter a loud, protraced, mournful sound or cry, as dogs
      and wolves often do.

            And dogs in corners set them down to howl.
                                                  --Drayton.

            Methought a legion of foul fiends Environ'd me
            about, and howled in my ears.         --Shak.

   2. To utter a sound expressive of distress; to cry aloud and
      mournfully; to lament; to wail.

            Howl ye, for the day of the Lord is at hand. --Is.
                                                  xiii. 6.

   3. To make a noise resembling the cry of a wild beast.

            Wild howled the wind.                 --Sir W.
                                                  Scott.

   {Howling monkey}. (Zo["o]l.) See {Howler}, 2.

   {Howling wilderness}, a wild, desolate place inhabited only
      by wild beasts. --Deut. xxxii. 10.

Source : WordNet®

howling
     adj 1: noisy with or as if with loud cries and shouts; "a crying
            mass of rioters"; "a howling wind"; "shouting fans";
            "the yelling fiend" [syn: {crying}, {yelling}, {shouting}]
     2: extraordinarily good; used especially as intensifiers; "a
        fantastic trip to the Orient"; "the film was fantastic!";
        "a howling success"; "a marvelous collection of rare
        books"; "had a rattling conversation about politics"; "a
        tremendous achievement" [syn: {fantastic}, {howling(a)}, {marvelous},
         {marvellous}, {rattling(a)}, {terrific}, {tremendous}, {wonderful},
         {wondrous}]
     n : a long loud emotional utterance; "he gave a howl of pain";
         "howls of laughter"; "their howling had no effect" [syn:
         {howl}, {ululation}]