Butternut is a tree native to North America that produces edible nuts with a rich, buttery flavor. The butternut tree grows wild in forests from Canada down through the eastern United States, and pioneers and Native Americans relied on its nuts as an important food source. The nuts have hard, ridged shells that you crack open to reach the oily, sweet kernel inside, which tastes somewhat like a walnut but milder and, true to the name, more buttery.

The wood from butternut trees is light-colored and easy to carve, making it popular for furniture and woodworking. During the American Civil War, Confederate soldiers sometimes wore uniforms dyed with butternut bark, which created a tan or brownish color. Because of this, Union soldiers nicknamed them “butternuts.”

The word can also refer to butternut squash, a completely different plant. This winter squash has tan skin and sweet orange flesh that becomes smooth and creamy when cooked. Though the squash and the tree aren't related, both earned the “butternut” name for their rich, buttery qualities. When you see butternut in a recipe, it almost always means the squash, while butternut referring to the tree appears more often in nature guides or history books.