1. to shout or call out loudly to attract attention or to urge on (especially hunting dogs)
Usage: often used in hunting contexts; can be transitive or intransitive

1. a loud shout or call

1. used as an exclamation to attract attention or express surprise
Usage: archaic or literary

Examples

• The hunter halloed to his dogs to drive the fox from the brush.
• She let out a halloo across the valley to signal her friends.
• Halloo! Can you hear me from over there?
• The riders halloed as they galloped across the field.
• A distant halloo echoed through the forest.
• He halloed at the top of his lungs to get their attention.