Butternut/ˈbʌtərnʌt/ Definition 1 of 4Pro Tip 1/2Specific Tree Understand 'butternut' refers to a North American tree, not any kind of tree. The butternut is native to this region, unlike tropical trees. Pro Tip 2/2Seasonal Changes 'Butternut' trees experience change, losing leaves in fall, which can be poetic. Walking by the butternut trees, the ground was covered in gold.