Definitions of howl:

• noun:   a long loud emotional utterance

  Example: "He gave a howl of pain"

• noun:   a loud sustained noise resembling the cry of a hound

  Example: "The howl of the wind made him restless"

• noun:   the long plaintive cry of a hound or a wolf
• verb:   emit long loud cries

  Example: "Howl with sorrow"

• verb:   cry loudly, as of animals

  Example: "The coyotes were howling in the desert"

• verb:   laugh unrestrainedly and heartily
• verb:   make a loud noise, as of wind, water, or vehicles

  Example: "The wind was howling in the trees"