[1] : The Collaborative International Dictionary of English v.0.48

hardtack \hard"tack`\ or hard-tack
\hard"-tack`\haumrd"ta^k`, 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
      1913 webster

   2. any of several mahogany trees, esp. the cercocarpus
      betuloides. --mw10
      pjc
see also:
pilot biscuit pilot bread ship biscuit ship bread cercocarpus betuloides 

[2] : WordNet (r) 2.0

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
see also:
pilot biscuit pilot bread sea biscuit ship biscuit 

Hardtack >> H Words
Hardtack, definition of term: Hardtack
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