(1):

(n.) Any species of ciliated Infusoria belonging to the genus Stentor and allied genera, common in fresh water. The stentors have a bell-shaped, or cornucopia-like, body with a circle of cilia around the spiral terminal disk. See Illust. under Heterotricha.

(2):

(n.) A howling monkey, or howler.

(3):

(n.) A herald, in the Iliad, who had a very loud voice; hence, any person having a powerful voice.