complex Definition in the Cambridge English Dictionary
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Definition of “complex” - English Dictionary

Definition of "complex" - American English Dictionary

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complexadjective

 us   /kəmˈpleks, ˈkɑm·pleks/
having many ​partsrelated to each other in ​ways that may be ​difficult to ​understand: a complex ​surgicalprocedure The ​question of who is ​legallyresponsible is a complex ​issue.
complexity
noun [C/U]  us   /kəmˈplek·sɪ·t̬i/
[U] You must ​understand the ​variety and complexity of ​tasksassigned to the ​police.

complexnoun [C]

 us   /ˈkɑm·pleks/

complex noun [C] (BUILDING)

a ​group of ​buildings that are ​related, or a ​largebuilding having different ​parts: an ​apartment complex for ​elderlypeople

complex noun [C] (ATTITUDES)

a ​group of ​attitudes and ​feelings that ​influence a person’s ​behavior, often in a ​negative way: an ​inferiority complex
(Definition of complex from the Cambridge Academic Content Dictionary © Cambridge University Press)

Definition of "complex" - British English Dictionary

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complexadjective

uk   /ˈkɒm.pleks/ /kəmˈpleks/  us   /ˈkɑːm-/
B2 involving a lot of different but ​relatedparts: a complex ​molecule/​carbohydrate a complex ​network of ​roads a complex ​procedure The ​company has a complex ​organizationalstructure.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 ​straightforwardanswer. The film's ​plot was so complex that I couldn't ​follow it.
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complexnoun [C]

uk   /ˈkɒm.pleks/  us   /ˈkɑːm-/

complex noun [C] (BUILDING)

C1 a ​largebuilding with ​variousconnectedrooms or a ​relatedgroup of ​buildings: a ​shopping/​sports and ​leisure complexUS They ​live in a ​largeapartment complex.
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complex noun [C] (BAD FEELING)

C2 a ​particular anxiety or ​unconsciousfear that a ​person has, ​especially as a ​result of an ​unpleasantexperience that they have had in the past or because they have a ​lowopinion of ​their own ​worth: an ​inferiority complex I ​think he's got a complex about being ​bald. Don't go on about her ​weight - you'll give her a complex!
(Definition of complex from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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