Quick meaning
The first programme that runs when a computer starts, before the operating system loads.
Think of it like this
Like the ignition system of a car — it starts everything else.
Where you may see this
You may hear this when buying a device, asking for repairs, or checking phone and computer settings.
Why it matters
Understanding the hardware term helps you choose the right device and explain problems more clearly when asking for help.
Say it simply
BIOS means: The first programme that runs when a computer starts, before the operating system loads.