Pronunciation: (thach),[key] —n. 1. Also,thatching.a material, as straw, rushes, leaves, or the like, used to cover roofs, grain stacks, etc.
2. a covering of such a material.
3. the leaves of various palms that are used for thatching.
4. something resembling thatch on a roof, esp. thick hair covering the head: a thatch of unruly red hair. 5. Hort.a tightly bound layer of dead grass, including leaves, stems, and roots, that builds up on the soil surface at the base of the living grass of a lawn.
—v.t. 1. to cover with or as if with thatch.
2. Hort.to remove thatch from (a lawn); dethatch.