breadroot

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A perennial herb (Psoralea esculenta) in the pea family, native to prairies and plains in central North America, and having a tuberous, starchy root that was an important food for many Native Americans. Also called prairie potato.

Century Dictionary and Cyclopedia

1. n. A plant of the genus Psoralea, the P. esculenta. See Psoralea.

Wiktionary

1. n. The edible root of a leguminous plant (Psoralea esculenta).

GNU Webster's 1913

1. n. (Bot.) The root of a leguminous plant (Psoralea esculenta), found near the Rocky Mountains. It is usually oval in form, and abounds in farinaceous matter, affording sweet and palatable food.

WordNet 3.0

1. n. densely hairy perennial of central North America having edible tuberous roots