HO (3)

{ Ho, Hoa } (hō), interj. [[Cf. F. & G. ho.]] 1. 1. Halloo! attend! — a call to excite attention, or to give notice of approach. “What noise there, ho?” Shak. “Ho! who's within?” Shak.
2. 2. [[Perhaps corrupted fr. hold; but cf. F. hau stop! and E. whoa.]] Stop! stand still! hold! — a word now used by teamsters, but formerly to order the cessation of anything. [Written also whoa, and, formerly, hoo.]
The duke . . . pulled out his sword and cried “Hoo!” Chaucer. An herald on a scaffold made an hoo. Chaucer.