halloo

n.

  1. A loud exclamation; a call to invite attention or to incite a person or an animal; a shout.
  2. An exclamation to call attention or to encourage one.

v. i.

  1. To cry out; to exclaim with a loud voice; to call to a person, as by the word halloo.

v. t.

  1. To encourage with shouts.
  2. To chase with shouts or outcries.
  3. To call or shout to; to hail.