What is the meaning of hollo?

noun

• A very loud utterance (like the sound of an animal. )
  • usage: "his bellow filled the hallway"
  • synonyms: bellow, bellowing, holla, holler, hollering, holloa, roar, roaring, yowl

verb

• Encourage somebody by crying hollo.
• Cry hollo.
• Utter a sudden loud cry.
  • usage: "she cried with pain when the doctor inserted the needle"; "I yelled to her from the window but she couldn't hear me"
  • synonyms: shout, shout out, cry, call, yell, scream, holler, squall