Emily Dickinson Lexicon

LU-NET', or LU-NETTE', n. [Fr. lunette, from lune, the moon.]

1. In fortification, an enveloped counterguard, or elevation of earth made beyond the second ditch, opposite to the places of arms; or a covered place before the courtine, consisting of two faces that form an angle inward. It is commonly raised in ditches full of water, to serve instead of fausse brays, to dispute the enemy's passage of the ditch. – Encyc. Trevoux.
2. In the manege, a half horse-shoe, which wants the spunge, or that part of the branch which runs toward the quarters of the foot. – Encyc.
3. A piece of felt to cover the eye of a vicious horse. – Encyc.