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1. A shout to attract attention
   "he gave a great halloo but no one heard him"

1. Urge on with shouts
   "halloo the dogs in a hunt"
    
2. Shout 'halloo', as when greeting someone or attracting attention

Derived forms: halloos, hallooing, hallooed

Type of: call, cry, egg, egg on, holler [informal], hollo [non-standard], incite, outcry, prod, scream, shout, shout out, squall, vociferation, yell

Encyclopedia: Halloo