Read-Only Memory (ROM) is a type of computer memory that is used to store permanent data and instructions. Unlike Random Access Memory (RAM), which is temporary and can be changed, ROM retains its information even when the power is turned off. This makes it ideal for storing firmware, which is essential software that helps boot up a computer or device. ROM comes in various forms, including PROM, EPROM, and EEPROM, each with different capabilities for data modification. It is commonly found in devices like computers, smartphones, and game consoles, ensuring that critical system information is always available when needed.