n. [ Perh. fr. ah + lo; cf. AS. ealā, G. halloh, F. haler to set (a dog) on. Cf. Hollo, interj. ] A loud exclamation; a call to invite attention or to incite a person or an animal; a shout. [ 1913 Webster ]

List! List! I hear
Some far off halloo break the silent air. Milton. [ 1913 Webster ]

v. i. [ imp. & p. p. Hallooed p. pr. & vb. n. Hallooing. ] To cry out; to exclaim with a loud voice; to call to a person, as by the word halloo. [ 1913 Webster ]

Country folks hallooed and hooted after me. Sir P. Sidney. [ 1913 Webster ]

v. t. 1. To encourage with shouts. [ 1913 Webster ]

Old John hallooes his hounds again. Prior. [ 1913 Webster ]

2. To chase with shouts or outcries. [ 1913 Webster ]

If I fly . . . Halloo me like a hare. Shak. [ 1913 Webster ]

3. To call or shout to; to hail. Shak. [ 1913 Webster ]

interj. [ OE. halow. See Halloo, n. ] An exclamation to call attention or to encourage one. Now mostly replaced by hello. [ 1913 Webster ]