Definition of "hallo"

hallo

/həˈləʊ/

interjection
1. Alternative form of hello
2. (dated) A cry of surprise.
  Quotations
  It sounds like a sum in the rule of three. The answer should give us the — But hallo! here are the accredited representatives of the law.
  1890, A[rthur] Conan Doyle, The Sign of the Four, London: Spencer Blackett
noun
plural hallos or halloes
1. The cry "hallo!"
2. A shout of exultation.
verb
third-person singular simple present hallos or halloes, present participle halloing, simple past and past participle halloed
1. (intransitive) To shout, or to call with a loud voice.
2. (transitive) To chase while shouting "hallo!"
3. (transitive) To cry "hallo" (to someone).
4. (transitive) To shout (something).