What is the meaning of Halloo?
Used to greet someone, or to catch their attention.
Used in hunting to urge on the pursuers.
A shout of halloo.
To shout halloo.
To encourage with shouts; to egg (someone) on.
To chase with shouts or outcries.
To call or shout to; to hail.
To shout (something).
Source: wiktionary.org