thatch

Straw, rushes, or similar, used for making or covering the roofs of buildings, or of stacks of hay or grain.countableuncountable

• Just over halfway up, we reached the Human settlement with its houses of stone and wood and thatch. This was a prewar place.

Any of several kinds of palm, the leaves of which are used for thatching.Caribbeancountableuncountable

A buildup of cut grass, stolons or other material on the soil in a lawn.countableuncountable

• Mark Ladd, the venue’s assistant director of operations, notes that the fake greenery looks authentic: the height and colour of the blades are varied, with a few brown ones thrown in to emulate dead thatch.

Any strawlike material, such as a person's hair.broadlycountablefiguratively

• Brown was a compact dark-skinned man in his forties, with strong features and a dense thatch of brown hair that sprang from his crown at an angle, though it had been brushed to either side of an indeterminate part.
• An outgoing, story-telling Irishman from Butte, Montana, with his thatch of red hair and sandpapered face, Matt was the quintessential imp.

To cover the roof with straw, reed, leaves, etc.