complex

[kuhm-pleks, kom-pleks, kom-pleks]

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.

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

/ 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

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

Word History and Origins

Origin of complex¹

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

Word History and Origins

Origin of complex¹

C17: from Latin complexus, from complectī to entwine, from com- together + plectere to braid

Example Sentences

"They provided tectonically and geochemically stable marine environments with presumably elevated levels of nutrients and oxygen, which in turn were critical for more complex lifeforms to evolve and diversify on our planet."

Read more on Science Daily

Rhian Wyn said bereaved families are often "left completely on their own", while also having to deal with complex official procedures that follow.

Read more on BBC

The group suggests a complex network as well as a single organism.

Read more on The Wall Street Journal

The third bloc was the Sunni Islamist alliance, which has a complex and ambiguous relationship with American power.

Read more on The Wall Street Journal

This earnings season comes at a complex moment for the insurance industry.

Read more on Barron's

Related Words

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