A passcode is a series of letters, numbers, or symbols used to gain access to a secure system or device. There are several synonyms for passcode, including password, PIN, combination, code, access code, secret code, passphrase, and security code. Each of these terms refers to the same concept of a unique code that must be entered correctly to access restricted information or systems. Passcodes are commonly used in various technologies, such as computers, smartphones, and bank accounts. It is important to choose a strong and secure passcode to prevent unauthorized access to sensitive data.