the GNU version of the Collaborative International Dictionary of English
n. The breastplate of the armor of a horse. See peytrel.
The Century Dictionary and Cyclopedia
n. A piece of armor that protected the breast of a horse. The use of the poitrel lingered long after the other parts of the bards had been abandoned.
Word Usage
"For every stud of silver on his casque of bronze he must have fought in a pitched battle; and for each tuft of hair upon his charger’s poitrel he must have slain a foe in hand-to-hand encounter."