{ Ho, Hoa } (hō), interj. [Cf. F. & G. ho.] 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. [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.