Stentor

The old man stood up, shouted an order in the voice of a Stentor, and waved his hand.
The Norsemen in the West|R.M. Ballantyne
Nay, but he could not; he lay in chains with a gag in his mouth, that might have smothered the voice of Stentor.
Quintus Claudius, Volume 1 of 2|Ernst Eckstein
Every man is like "Stentor of the brazen voice," whose shout, as Homer says in the Iliad, "was as the shout of fifty men."
The Irish on the Somme|Michael MacDonagh
Stentor, stent′or, n. a very loud-voiced herald in the Iliad, hence any person with a remarkably loud voice: the ursine howler.
Chambers's Twentieth Century Dictionary (part 4 of 4: S-Z and supplements)|Various

The Stentor, from its location below the alga, could not reach the starch grains without altering its position.
The Dawn of Reason|James Weir

British Dictionary definitions for Stentor (1 of 2)

stentor

/ (ˈstɛntɔː) /

noun

a person with an unusually loud voice

any trumpet-shaped protozoan of the genus Stentor, having a ciliated spiral feeding funnel at the wider end: phylum Ciliophora (ciliates)

Word Origin for stentor

C19: after Stentor

British Dictionary definitions for Stentor (2 of 2)

Stentor

/ (ˈstɛntɔː) /

noun

Greek myth a Greek herald with a powerful voice who died after he lost a shouting contest with Hermes, herald of the gods

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012