uefi

In computing terms the difference between bios and uefi

is that bios is acronym of Basic Input/Output System|lang=en while uefi is Unified Extensible Firmware Interface: a specification that defines a software interface between an operating system and platform firmware.

As a noun BIOS

is built-in operating system.

As a proper noun UEFI is

Unified Extensible Firmware Interface: a specification that defines a software interface between an operating system and platform firmware.

As a proper noun uefi is

(computing) (unified extensible firmware interface): a specification that defines a software interface between an operating system and platform firmware.