What is a "key lime"?

Key lime, also known as the Mexican lime or West Indian lime, is a citrus fruit native to Southeast Asia and widely cultivated in tropical regions around the world, named after the Florida Keys. Small, round, and yellow when ripe, with a thin, smooth skin and highly aromatic juice, key limes are known for their distinctive tart flavor, more intense than other lime varieties. Commonly used in cooking and baking, particularly in desserts like key lime pie, as well as in beverages and sauces, they are prized for their unique taste and aroma, adding a zesty kick to a variety of dishes.