The Collaborative International Dictionary of English v.0.48:

Danegeld \Dane"geld`\, Danegelt \Dane"gelt`\, n. [AS. danegeld.
   See Dane, and Geld, n.] (Eng. Hist.)
   An annual tax formerly laid on the English nation to buy off
   the ravages of Danish invaders, or to maintain forces to
   oppose them. It afterward became a permanent tax, raised by
   an assessment, at first of one shilling, afterward of two
   shillings, upon every hide of land throughout the realm.
   --Wharton's Law Dict. Tomlins.
   [1913 Webster]