- A tuft, as of grass, twigs, hair, or the like; especially,
a dense tuft or bunch of grass or sedge. - Same as Tussock grass, below. - A caterpillar of any one of numerous species of bombycid
moths. The body of these caterpillars is covered with hairs which form
long tufts or brushes. Some species are very injurious to shade and
fruit trees. Called also tussock caterpillar. See Orgyia.