A "cookie" is a small piece of data that a website stores on your computer or device when you visit it. Cookies help websites remember your preferences, like your login information or items in your shopping cart. This makes your browsing experience smoother and more personalized. There are different types of cookies, such as session cookies, which are temporary and deleted when you close your browser, and persistent cookies, which stay on your device for a set period. While cookies can enhance your online experience, they also raise privacy concerns, as they can track your browsing habits across different sites.