Meaning of COMPLEX in English

COMPLEX

adjective , noun

■ adjective / ˈkɒmpleks; NAmE kəmˈpleks; ˈkɑːm-/

1.

made of many different things or parts that are connected; difficult to understand

SYN complicated :

complex machinery

the complex structure of the human brain

a complex argument / problem / subject

2.

( grammar ) ( of a word or sentence ) containing one main part (= the root of a word or main clause of a sentence) and one or more other parts ( affixes or subordinate clauses )

—compare compound adjective

■ noun /ˈkɒmpleks; NAmE ˈkɑːm-/

1.

a group of buildings of a similar type together in one place :

a sports complex

an industrial complex (= a site with many factories)

➡ note at building

2.

a group of things that are connected :

This is just one of a whole complex of issues.

3.

(especially in compounds) a mental state that is not normal :

to suffer from a guilt complex

—see also inferiority complex , Oedipus complex , persecution complex

4.

if sb has a complex about sth, they are worried about it in way that is not normal

••

WORD ORIGIN

mid 17th cent. (in the sense group of related elements ): from Latin complexus , past participle (used as a noun) of complectere embrace, comprise, later associated with complexus plaited; the adjective is partly via French complexe .

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.