The term "butternut" has multiple meanings depending on its context.
1) In a general sense, it can refer to any type of nut that is similar in texture and flavor to butter when roasted. This includes nuts from various species such as the white walnut or heartnut.
2) It can also be used to describe a specific variety of winter squash known for its sweet, creamy flesh and oblong shape. The butternut squash is one of the most popular types of winter squash and is commonly used in cooking and baking.