A genus of plants, called Rhamnus, of many species. The common purging buck-thorn grows to the height of 12 or 14 feet, and bears a black berry, which, when green, is used to dye yellow, and when ripe, green. The bark also dyes yellow. The sea buck-thorn is a genus of plants, called Hippophae.

A genus (Rhamnus) of shrubs or trees. The shorter branches of some species terminate in long spines or thorns. See Rhamnus.