'Holloa' definitions:

Definition of 'holloa'

(from WordNet)
noun
A very loud utterance (like the sound of an animal); "his bellow filled the hallway" [syn: bellow, bellowing, holla, holler, hollering, hollo, holloa, roar, roaring, yowl]

Definition of 'Holloa'

From: GCIDE
  • Holloa \Hol*loa"\, interj., n. & v. i. Same as Hollo. [1913 Webster]