Emily Dickinson Lexicon

BUT'TER-NUT, n. [butter and nut.]

The fruit of an American tree, the Juglans cinerea; so called from the oil it contains. The tree bears a resemblance, in its general appearance, to the black walnut, so called. It is sometimes called Oilnut and White walnut. The tree is called also Butternut or Butternut tree. Dr. M. Cutler calls it Juglans cathartica. It is the Juglans cinerea of others. – Belknap.