Nouns

(n)bellow, bellowing, holla, holler, hollering, hollo, holloa, roar, roaring, yowla very loud utterance (like the sound of an animal)“his bellow filled the hallway”

Verbs

(v)bawl, bellowshout loudly and without restraint
(v)bellow, roarmake a loud noise, as of animal“The bull bellowed”