Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “complex”

complex

adjective     /ˈkɒm.pleks/ /kəmˈpleks/ US  /ˈkɑːm-/
B2 involving a lot of different but related parts: a complex molecule/carbohydrate a complex network of roads a complex procedure The company has a complex organizational structure.ComplexityDifficult to understand B2 difficult to understand or find an answer to because of having many different parts: It's a very complex issue to which there is no straightforward answer. The film's plot was so complex that I couldn't follow it.Difficult to understandComplicated and difficult to doPuzzle and confuse
(Definition of complex adjective from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
Focus on the pronunciation of complex

Browse related topics

You are looking at an entry to do with Difficult to understand, but you might be interested in these topics from the Knowing and understanding topic area:

Definitions of “complex” in other dictionaries

Word of the Day

neighbourly

friendly or helpful

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