complex

American  

[kuhm-pleks, kom-pleks, kom-pleks] / kəmˈplɛks, ˈkɒm plɛks, ˈkɒm plɛks /

adjective

1. composed of many interconnected parts; compound; composite.

   a complex highway system.

2. characterized by a very complicated or involved arrangement of parts, units, etc..

   complex machinery.

   Antonyms:

   simple

3. so complicated or intricate as to be hard to understand or deal with.

   a complex problem.

   Synonyms:

   labyrinthine , tangled , knotty

   Antonyms:

   simple

4. Grammar.

   1. (of a word) consisting of two parts, at least one of which is a bound form, as childish, which consists of the word child and the bound form -ish.

   2. complex sentence.

5. Mathematics.  pertaining to or using complex numbers.

   complex methods; complex vector space.

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noun

1. an intricate or complicated association or assemblage of related things, parts, units, etc..

   the entire complex of our educational system; an apartment complex.

   Synonyms:

   labyrinth , tangle , web , network

2. Psychology.  a system of interrelated, emotion-charged ideas, feelings, memories, and impulses that is usually repressed and that gives rise to abnormal or pathological behavior.

3. a fixed idea; an obsessive notion.

4. Mathematics.

   1. an arbitrary set of elements of a group.

   2. a collection of simplexes having specified properties.

5. Also called coordination compound.  Chemistry.  a compound in which independently existing molecules or ions of a nonmetal complexing agent form coordinate bonds with a metal atom or ion.

6. Biochemistry.  an entity composed of molecules in which the constituents maintain much of their chemical identity.

   receptor-hormone complex, enzyme-substrate complex.

verb (used with object)

1. Chemistry.  to form a complex with.

verb (used without object)

1. Chemistry.  to form a complex.

complex British  

/ ˈkɒmplɛks /

adjective

1. made up of various interconnected parts; composite

2. (of thoughts, writing, etc) intricate or involved

3. grammar

   1. (of a word) containing at least one bound form

   2. (of a noun phrase) containing both a lexical noun and an embedded clause, as for example the italicized parts of the following sentence: I didn't know the man who served me

   3. (of a sentence) formed by subordination of one clause to another

4. maths of or involving one or more complex numbers

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noun

1. a whole made up of interconnected or related parts

   a building complex

2. psychoanal a group of emotional ideas or impulses that have been banished from the conscious mind but that continue to influence a person's behaviour

3. informal  an obsession or excessive fear

   he's got a complex about cats

4. Also called: coordination compound.  a chemical compound in which molecules, groups, or ions are attached to a central metal atom, esp a transition metal atom, by coordinate bonds

5. any chemical compound in which one molecule is linked to another by a coordinate bond

Usage

Complex is sometimes wrongly used where complicated is meant. Complex is properly used to say only that something consists of several parts. It should not be used to say that, because something consists of many parts, it is difficult to understand or analyse

Other Word Forms

• complexly adverb
• complexness noun
• overcomplex adjective
• quasi-complex adjective
• quasi-complexly adverb
• supercomplex adjective
• uncomplex adjective
• uncomplexly adverb
• uncomplexness noun

Etymology

Origin of complex

First recorded in 1645–55; 1905–10 complex for def. 7; adjective from Latin complexus, past participle of complectī, complectere “to embrace, encompass, include,” equivalent to complect- ( complect ) + -tus past participle suffix; noun from Late Latin complexus “totality, complex” ( Latin: “inclusion, grasping, embrace”), equivalent to complect(ere) + -tus suffix of verb action; reanalysis of the Latin verb as “to intertwine (completely)” influenced sense of the adjective

Example Sentences

Throughout his medical records, I can see glimpses of who my dad is, who he’s always been—a complex soul who can be both affable and combative, cooperative and recalcitrant, depending on his mood.

From Salon

Some users praised its capabilities for quick tasks but said they still rely on bigger AI models like those from Anthropic for more complex work.

From The Wall Street Journal

Split between its rival language camps, Belgium's complex political patchwork has long been seen as borderline dysfunctional.

From Barron's

"I want you to know that your parents, your grandparents and many Spaniards, united, managed to carry out an exemplary transition" in "very complex circumstances", he added with a Spanish flag fluttering in the background.

From Barron's

“We are applying the statutes as Congress wrote them, which are complex and sometimes require us to jump through a lot of hoops to get there.”

From The Wall Street Journal

Related Words

• complicated
• convoluted
• disturbing
• intricate
• obscure
• perplexing
• sophisticated