A zester is a kitchen tool used to remove the outer zest of citrus fruits like lemons, limes, and oranges. It typically features a small, sharp blade or a series of tiny holes that scrape off the colorful outer layer of the fruit's peel without cutting into the bitter white pith underneath. This zest adds intense flavor and aroma to various dishes and beverages. Zesters come in different designs, including handheld versions and those that resemble graters. They are often made of stainless steel for durability and easy cleaning. Using a zester can enhance the taste of desserts, marinades, and cocktails, making it a valuable tool for home cooks and professional chefs alike.