means Thatch is a roof covering made from dry plant material like straw, reeds, or rushes, layered thickly to shed rain; the word also means a thick mass of something, especially a person's hair.

from From Old English 'þæc,' meaning a roof or covering, with the related verb 'þeccan,' to cover. It belongs to a deep Germanic family — a cousin of German 'Dach' (roof) and 'decken' (to cover) — and reaches back further to a root meaning simply 'to cover,' possibly related to Latin 'tegere' (to cover, as in 'tegument' and 'protect'). The same ancient impulse that named the roof named the thing that hides and shelters; over time the noun ('thack') and verb drifted, and 'thatch' settled into both the stuff on the roof and the unruly stuff on your head.