Alphanumeric refers to a set of characters that includes both letters and numbers. This combination allows for a wider range of symbols to be used in various applications, such as passwords, usernames, and coding. For example, a password like "User123" is alphanumeric because it contains both letters and digits. In computing, alphanumeric characters are essential for data entry and programming. They help create more complex identifiers and enhance security by making it harder for unauthorized users to guess passwords. Common uses of alphanumeric characters can be found in systems like databases, software applications, and online forms.