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
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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 .