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1. A very loud utterance (like the sound of an animal)
   "his bellowing filled the hallway";
   - bellow, holla [archaic], holler [informal], hollering [informal], hollo [non-standard], holloa [rare], roar, roaring, yowl

1. Shout loudly and without restraint
   - bawl
    
2. Make a loud noise, as of an animal
   "The bull bellowed";
   - roar

Derived forms: bellowings

Type of: call, cry, emit, let loose, let out, outcry, shout, utter, vociferation, yell

Encyclopedia: Bellow, Adam