tussock

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A clump or tuft, as of growing grass.

from The Century Dictionary.

• noun A clump, tuft, or small hillock of growing grass.
• noun Same as tuft, 1.
• noun A tussock-moth, as of the genus Orgyia (which see); a vaporer: so called from the tufted larvæ.
• noun Same as tussock-grass.

from the GNU version of the Collaborative International Dictionary of English.

• noun A tuft, as of grass, twigs, hair, or the like; especially, a dense tuft or bunch of grass or sedge.
• noun (Bot.) Same as Tussock grass, below.
• noun (Zoöl.) 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.
• noun (Bot.) Any kind of sedge (Carex) which forms dense tufts in a wet meadow or boggy place.
• noun (Zoöl.) the imago of any tussock caterpillar. They belong to Orgyia, Halecidota, and allied genera.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A tuft or clump of green grass or similar verdure, forming a small hillock.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a bunch of hair or feathers or growing grass