Source : Webster's Revised Unabridged Dictionary (1913)

Thatch \Thatch\, v. t. [imp. & p. p. {Thatched}; p. pr. & vb. n.
   {Thatching}.] [From {Thatch}, n.: cf. OE. thecchen, AS.
   ?eccean to cover.]
   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.