The Collaborative International Dictionary
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
Wiktionary
n. hardtack
WordNet
n. very hard unsalted biscuit or bread; a former ship's staple [syn: hardtack, pilot biscuit, sea biscuit, ship biscuit]
Usage examples of "pilot bread".
Siri had taken a tray with tea and pilot bread to him the previous afternoon, as he had requested, but she had refused to linger when he invited her inside.
Lockwood kept a list of the dishes he missed most: turkey stuffed with oysters, Boston pilot bread, oatmeal muffins, corn fritters.
This consisted of oatmeal and cream kept hermetically sealed in glass, a dish of roast grouse, coffee, pilot bread, a bottle of Sauterne, and another of Rhine wine.