Squash, often mistaken for just a sport or a vegetable, actually refers to a family of plants. Within this family, there are dozens of varieties, broadly categorized into summer and winter squash. Summer squash includes zucchini and yellow squash, which are harvested while tender. Winter squash, like butternut, acorn, and spaghetti squash, are harvested when fully mature, featuring hard skins and longer shelf lives.