interjection
Used to greet someone, or to catch their attention.
Used in hunting to urge on the pursuers.
noun
A shout of halloo.
verb
(intransitive) To shout halloo.
(transitive) To encourage with shouts; to egg (someone) on.
(transitive) To chase with shouts or outcries.
(transitive) To call or shout to; to hail.
(transitive) To shout (something).