Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English


English definition of “worm”


noun [C]     /wɜːm/ IT
a computer program that can send copies of itself to other computers and is designed to prevent the computers from working normally : When users click an infected attachment , the worm opens a "back door " that hackers can use.
(Definition of worm noun from the Cambridge Business English Dictionary © Cambridge University Press)
Focus on the pronunciation of worm

Definitions of “worm” in other dictionaries

Word of the Day

grand prix

one of a series of important international races for very fast and powerful cars

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More