exclam.
used to incite dogs to the chase during a hunt.
▸used to attract someone's attention.
n.
a cry of ‘halloo’.
v.
(halloos, hallooing, hallooed)
cry or shout ‘halloo’.
Etymology
C16: prob. from the obs. v. hallow ‘pursue or urge on with shouts’, from imitative OFr. haloer.