BIOS is Firmware for computers. As you continue to read and learn about computers, you will gain understanding about BIOS, UEFI, EFI, and so on.
BIOS is an acronym for Basic Input/Output System and also known as System BIOS, ROM BIOS, or PC BIOS. It is a type of Firmware used during the booting process (power-on/start up) on IBM PC compatible computers. BIOS Firmware is built into PCs, and it is the first software they run when powered on. The name itself originates from the Basic Input/Output System used in the CP/M operating system in 1975.
Firmware is a combination of persistent memory, program code, and the data stored in it. Typical examples of devices containing Firmware are embedded systems such as traffic lights, consumer appliances, digital watches, computers, computer peripherals, mobile phones, and digital cameras. The Firmware contained in these devices provides the control program for the device.