φορβεία

From LSJ

γνοίης ὅσσον ὄνων κρέσσονες ἡμίονοι → you know how much better are donkeys from mules

Source

Middle Liddell

φορβεία, ἡ, φορβή
I. a feeding-string, i. e. the halter by which a horse is tied to the manger, Xen.
II. a mouthband of leather put like a halter round the lips of pipers, to assist them in blowing, Ar.