hard·tack /-ˌtæk/
  硬麵餅
  Hard·tack or Hard-tack n.
  1. A name given by soldiers and sailors to a kind of unleavened hard biscuit or sea bread.  Called also pilot biscuit, pilot bread, ship biscuit and ship bread
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  hardtack
       n 1: very hard unsalted biscuit or bread; a former ship's staple
            [syn: pilot biscuit, pilot bread, sea biscuit, ship
            biscuit]
       2: a mountain mahogany