A tumbleweed is a structural part of the above-ground anatomy of a number of species of plants. It is a diaspore that, once mature and dry, detaches from its root or stem and rolls due to the force of the wind. In most such species, the tumbleweed is in effect the entire plant apart from the root system, but in other plants, a hollow fruit or inflorescence might detach instead. Xerophyte tumbleweed species occur most commonly in steppe and arid ecosystems, where frequent wind and the open environment permit rolling without prohibitive obstruction.

Lepidium is a genus of plants in the mustard/cabbage family, Brassicaceae. The genus is widely distributed in the Americas, Africa, Asia, Europe, and Australia. It includes familiar species such as garden cress, maca, and dittander. General common names include peppercress, peppergrass, pepperweed, and pepperwort. Some species form tumbleweeds. The genus name Lepidium is a Greek word meaning 'small scale', which is thought to be derived from a folk medicine usage of the plant to treat leprosy, which cause small scales on the skin. Another meaning is related to the small scale-like fruit.