Emily Dickinson Lexicon

BUCK'LER, n. [W. bwceled; Fr. bouclier; Ir. buicleir.]

A kind of shields or piece of defensive armor, anciently used in war. It was composed of wood, or wicker woven together, covered with skin or leather, fortified with plates of brass or other metal, and worn on the left arm. On the middle was an umbo, boss, or prominence, very useful in causing stones and darts to glance off. The buckler often was four feet bong, and covered the whole body. – Encyc.