Trojan horse

noun

1

: someone or something intended to defeat or subvert from within usually by deceptive means

2

: a seemingly useful computer program that contains concealed instructions which when activated perform an illicit or malicious action (such as destroying data files)

also : the concealed instructions of such a program compare virus sense 3

Did you know?

After besieging the walls of Troy for ten years, the Greeks built a huge, hollow wooden horse, secretly filled it with armed warriors, and presented it to the Trojans as a gift for the goddess Athena, and the Trojans took the horse inside the city's walls. That night, the armed Greeks swarmed out and captured and burned the city. A Trojan horse is thus anything that looks innocent but, once accepted, has power to harm or destroy—for example, a computer program that seems helpful but ends up corrupting or demolishing the computer's software.

Examples of Trojan horse in a Sentence

They may be using the other corporation as a Trojan horse.

Word History

Etymology

from the large hollow wooden horse filled with Greek soldiers and introduced within the walls of Troy by a stratagem

First Known Use

1837, in the meaning defined at sense 1

Kids Definition

Trojan horse

noun

1

: one intended to undermine or subvert from within

2

: a seemingly useful computer program that contains concealed instructions which when activated perform an illicit or malicious action compare virus sense 3, worm sense 5

Etymology

from the large hollow wooden horse filled with Greek soldiers and brought within the walls of Troy as a trick during the Trojan War