Crabapples are small, tart apples - typically 1-2 inches across - that grow on wild and ornamental Malus trees closely related to the cultivated apple (Malus domestica), but smaller, more acidic, and rarely eaten out of hand. They're native to temperate regions of North America, Europe, and Asia, and come in red, yellow, green, and pink varieties.
Because of their high pectin content, crabapples are most often cooked down into jams, jellies, and preserves that set without added pectin; crabapple jelly is a classic accompaniment to roasted meats, game, and poultry. The fruit is also pressed into cider or wine, and some cooks pickle it or use it to flavor vinegar. Their intense tartness makes raw eating unappealing to most people, so nearly all culinary use involves cooking with sugar to balance the acidity.
Foraged and cultivated crabapples have been part of the diet in Europe, Asia, and North America for thousands of years, including use by many Native American tribes in stews, sauces, and as a sweetener. Today they're grown mainly as ornamental trees for their spring blossoms, with crabapple preserves remaining a minor but persistent presence in regional cooking, especially alongside pork, game, and root vegetables in the colder months.