Butternut :: Butternut (n.) An American tree (Juglans cinerea) of the Walnut family, and its edible fruit; -- so called from the oil contained in the latter. Sometimes called oil nut and white walnut..
Butternut :: Butternut (n.) The nut of the Caryocar butyrosum and C. nuciferum, of S. America; -- called also Souari nut..