Emily Dickinson Lexicon

BLUE, a. [blu. Sax. bleo, bleoh, bleow, color; D. blaauw; Ger. blau; Dan. blaae; Sw. blå, blue; Sw. bly, Dan. blye, Ger. blei, lead, so named from its color; Slav. plavu; Fr. bleu; Corn. blou.]

One of the seven colors, into which the rays of light divide themselves, when refracted through a glass prism. There are various shades of blue, as sky-blue, or azure, Prussian blue, indigo blue, small blue, &c. – Kirwan. Encyc. Prussian blue, a combination of the oxyd of iron with an acid called ferro-prussic. – Ure.