firewall

/ˈfaɪ.əˌwɔːl/noun

A program that watches data flowing into and out of a computer or network and blocks anything that appears dangerous.

Example sentences

“The company's firewall blocked the suspicious download.”
“Make sure your firewall is turned on before using public Wi-Fi.”

Originally a literal wall built to stop fire spreading between buildings or engine and cabin; the computing sense borrowed that image of a protective barrier.

technology

Related words

megabyteA unit of digital information equal to a million bytes, or one thousand kilobytes.streamingSending or playing audio or video over the internet as it arrives, without saving it first.processorA machine or person that handles or transforms something, such as the chip that runs a computer or an appliance that chops food.shortcutA key or group of keys you press together to give a computer a command quickly.interfaceThe place or means where two systems meet and interact with each other.notificationAn alert or message that a device or app shows to tell you about something, such as a new email or update.