HENNA, the name of a yellow pigment obtained from Lawsonia inermis, a plant of the nat. ord. Lythraceæ. It is much used in Egypt, Arabia, Persia, and throughout the East generally, for staining the nails of the fingers, the manes and hoofs of horses, &c.; and some have attributed the yellow tinge of the nails of the Egyptian mummies to the use of this dye, though probably without sufficient reason.