hollo in WordNet English dictionary

1. a very loud utterance (like the sound of an animal)
   "his bellow filled the hallway"
   bellow  bellowing  holla  holler  hollering  hollo  holloa  roar  roaring  yowl 
   

1. utter a sudden loud cry
   "she cried with pain when the doctor inserted the needle"; "I yelled to her from the window but she couldn't hear me"
   shout  shout out  cry  call  yell  scream  holler  hollo  squall 
   
2. cry hollo
   hollo 
   
3. encourage somebody by crying hollo
   hollo