noun

BIOS

BY-oss

BIOS (noun) means the low-level software stored on a chip on a computer's motherboard that runs the moment the machine is switched on, checks the hardware and then hands control to the operating system. Example: “He pressed Delete during start-up to get into the BIOS.”

noun

The low-level software stored on a chip on a computer's motherboard that runs the moment the machine is switched on, checks the hardware and then hands control to the operating system.

"He pressed Delete during start-up to get into the BIOS."

"The fan curve is set in the BIOS, not in Windows."

How to Use BIOS

Learner’s notes

In plain EnglishThe built-in software that wakes a computer up before Windows or macOS starts.

When to use it

Standard technical term, widely used by hobbyists. Pronounced as a word, not spelled out.

Memory tip

Say BY-oss. Take care that BIOS update is not the same as an operating system update.

Trace the full origin ↓

Easily confused with

UEFI firmware → operating system →

Common pairings

BIOS settings enter the BIOS BIOS update flash the BIOS BIOS password

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Fill the Gap

Can you complete this real example?

He pressed Delete during start-up to get into the _____.

Etymology

An acronym of basic input/output system.

Origin: English

Synonyms

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firmware UEFI boot firmware system firmware

Related Words

firmware

Rhymes for BIOS

Rios adios Helios Cheerios

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Frequently Asked Questions

What is the difference between BIOS and UEFI?

UEFI is the modern replacement for the traditional BIOS and does the same job of starting the machine, but supports larger drives, graphical setup screens and secure boot checks. Most people still say BIOS for the setup screen even on UEFI systems.

What is the difference between BIOS and an operating system?

The BIOS runs first and only long enough to test the hardware and find something to boot from. The operating system, such as Windows, macOS or Linux, then takes over and runs everything you actually use. The BIOS lives on a chip on the motherboard; the operating system lives on your drive.

What is CMOS and why does it hold a battery?

Settings you change in the BIOS, along with the clock, are kept in a small amount of memory on the motherboard powered by a coin cell. When that battery dies, the clock resets and custom settings revert to their defaults.

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