Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “bug”

bug

noun [C]     /bʌɡ/
ILLNESS B2 a bacteria or virus, or the illness that it causes: a flu / stomach bug Bacteria, moulds, germs and virusesNot fit and healthyThin or slender (of people)
COMPUTER B2 a mistake in a computer program: This program is full of bugs.Faults and mistakesComputer programming and software
INSECT B1 a small insectInsect names
EQUIPMENT a small, electronic piece of equipment used to secretly listen to people talkingSpying and espionage
be bitten by the bug/get the bug informal to develop a strong interest or enthusiasm for a particular activity: He's been bitten by the tennis bug.Excited, interested and enthusiastic
(Definition of bug noun from the Cambridge Learner's Dictionary © Cambridge University Press)

Browse related topics

You are looking at an entry to do with General & informal words for animals, but you might be interested in these topics from the Animals generally topic area:

More Learner's Dictionary definitions for “bug”

Definitions of “bug” in other dictionaries

Word of the Day

generous

willing to give money, help, kindness, etc., especially more than is usual or expected

Word of the Day

Blog

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