Correct spelling: anhydrous
1) without water; especially without water of crystallization
2) Destitute of water; as, anhydrous salts or acids.
It is obvious then, that when a high temperature is to be attained, anhydrous or full- dried peat is vastly superior to that which has simply been cured in the open air. "Peat and its Uses as Fertilizer and Fuel", , Samuel William Johnson.