Butternut (&unr_;), n. 1. (Bot.) 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.
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2. (Bot.) The nut of the Caryocar butyrosum and Caryocar nuciferum, of S. America; -- called also Souari nut.
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