Emily Dickinson Lexicon

CHAP'E-RON, n. [Fr.]

A hood or cap worn by the knights of the garter in their habits. It was anciently worn by men, women, nobles and populace; afterward appropriated to doctors and licentiates in colleges. The name then passed to certain devices placed on the foreheads of horses which drew the hearse in pompous funerals. – Johnson. Encyc.