Firewall

How to spell firewall

8 letters · 2 syllables

How to pronounce firewall

Say the part in capitals loudest.

What does firewall mean?

1. nounA security system that monitors and blocks unauthorised traffic between a computer network and the outside world.
2. nounA fire-resistant wall built to stop flames spreading between parts of a building or vehicle.

Firewall in a sentence

• The company firewall blocked the suspicious download before it reached any staff laptops.

• Building regulations required a brick firewall between the garage and the kitchen.

• Our IT team configured the firewall to allow only approved applications through.

• The mechanic checked the metal firewall separating the engine from the cabin.

Where does firewall come from?

Language of origin: Germanic

This is a transparent compound of two ancient native words: fire, from the Old English fyr, and wall, from the Old English weall. The wall element is itself a very early borrowing, since Anglo-Saxon took weall from the Latin vallum, meaning a rampart or line of palisades, long before the modern computing world existed. The literal sense came first: a firewall was a solid wall of brick or stone built between buildings, or inside a structure, to stop a blaze from spreading from one section to another. Engineers later reused the term for the metal partition separating an engine from the passenger compartment of a car or aircraft. Only in the late twentieth century did computing borrow the image, naming the software or hardware barrier that blocks hostile network traffic a firewall, and that vivid 'protective barrier' picture is what makes the spelling easy to recall once you see it as fire plus wall.

How the word is built

• fire (Old English fyr: fire)
• wall (Old English weall: rampart, barrier)