Definition of thatch

• n. - Straw, rushes, or the like, used for making or covering the roofs of buildings, or of stacks of hay or grain.
• n. - A name in the West Indies for several kinds of palm, the leaves of which are used for thatching.
• n. - To cover with, or with a roof of, straw, reeds, or some similar substance; as, to thatch a roof, a stable, or a stack of grain.