The Collaborative International Dictionary of English v.0.48:
Pumpernickel \Pump"er*nick`el\, n. [G.] A sort of bread, made of unbolted rye, which forms the chief food of the Westphalian peasants. It is acid but nourishing. [1913 Webster]WordNet (r) 3.0 (2006):
pumpernickel n 1: bread made of coarse rye flour [syn: black bread, pumpernickel]