The Collaborative International Dictionary
Hard-tack
Hardtack \Hard"tack`\ or Hard-tack \Hard"-tack`\(h[aum]rd"t[a^]k`), n.
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
Any of several mahogany trees, esp. the Cercocarpus betuloides.
--MW10
Usage examples of "hard-tack".
In the way of eatables and drinkables, we had stored in the stern of the Dolphin a generous bag of hard-tack (for the chowder), a piece of pork to fry the cunners in, three gigantic apple pies (bought at Pettingil's), half a dozen lemons, and a keg of spring water--the last-named articles were slung over the side, to keep it cool, as soon as we got under way.