English Wikipedia has an article on:

complex

Wikipedia

From French complexe, from Latin complexus, past participle of complector (“I entwine, encircle, compass, infold”), from com- (“together”) and plectere (“to weave, braid”). May be analyzed as com- +‎ -plex. See complect. Doublet of complexus.

Adjective

• (UK) IPA^(key): /ˈkɒm.plɛks/, /kəmˈplɛks/

• Audio (UK):

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• (US) enPR: kəmplĕks, kŏm'plĕks; IPA^(key): /kɑmˈplɛks/, /kəmˈplɛks/, /ˈkɑmplɛks/

• Audio (US); /kəmˈplɛks/:

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• Rhymes: -ɛks

Noun

• (UK) IPA^(key): /ˈkɒm.plɛks/

• Audio (UK):

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• (US) enPR: kŏm'plĕks, IPA^(key): /ˈkɑmplɛks/

• Audio (US):

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English Wikipedia has an article on:

complex number

Wikipedia

complex (comparative more complex or (nonstandard) complexer, superlative most complex or (nonstandard) complexest)

1. Made up of multiple parts; composite; not simple.

   a complex being; a complex idea

   The human body is a complex system made up of many layers.

   • 1689 (indicated as 1690), [John Locke], chapter 2, in An Essay Concerning Humane Understanding. […], London: […] Eliz[abeth] Holt, for Thomas Basset, […], →OCLC, book I, page 12:

     Ideas thus made up of several simple ones put together, I call complex; such as beauty, gratitude, a man, an army, the universe.

2. Not simple, easy, or straightforward; complicated.

   Synonyms: complicated, detailed, difficult, hard, intricate, involved, tough; see also Thesaurus:complex

   Antonyms: basic, easy, simple, simplex, straightforward; see also Thesaurus:easy

   • 1837, William Whewell, “Inductive Epoch of Hipparchus”, in History of the Inductive Sciences, from the Earliest to the Present Times. […], volume I, London: John W[illiam] Parker, […]; Cambridge, Cambridgeshire: J. and J. J. Deighton, →OCLC, book III (History of Greek Astronomy), section 2 (Estimate of the Value of the Theory of Eccentrics and Epicycles), page 183:

     If, when the actual motions of the heavens are calculated in the best possible way, the process is complex and difficult, and if we are discontented at this, nature, and not the astronomer, must be the object of our displeasure.

3. (mathematics, of a number) Having the form a + bi, where a and b are real numbers and i is (by definition) the imaginary square root of −1.

   complex number

   function of a complex variable

4. (mathematics, mathematical analysis, of a function) Whose range is a subset of the complex numbers.

   complex function

5. (mathematics, algebra) Whose coefficients are complex numbers; defined over the field of complex numbers.

   complex polynomial

   complex algebraic variety

6. (geometry) A curve, polygon or other figure that crosses or intersects itself.

• complexion
• (mathematics): symplectic

complex (plural complexes or (nonstandard) complices)

1. A network of interconnected systems.

   military-industrial complex

2. A collection of buildings with a common purpose, such as a university or military base.
   • 2008, BioWare, Mass Effect (Science Fiction), Redwood City: Electronic Arts, →ISBN, →OCLC, PC, scene: Protheans: Mars Ruins Codex entry:

     The south polar region of Promethei Planum developed a Bermuda Triangle reputation. Satellites detected intermittent mass concentrations and magnetic field shifts. In 2148, prospectors working near Deseado Crater discovered an underground complex: a Prothean observation post. The odd phenomena were generated by the operation and discharge of a mass effect core, struggling to function despite fifty millennia of neglect.

   • 2021 February 6, The Courier-Mail, Brisbane, page 4, column 1:

     A man at the complex said he had seen the often heavily made-up girls coming and going in luxury vehicles.

3. An assemblage of related things; a collection.
   • 1692–1717, Robert South, Twelve Sermons Preached upon Several Occasions, volume (please specify |volume=I to VI), London:

     This parable of the wedding supper comprehends in it the whole complex of all the blessings and privileges exhibited by the gospel.

   1. An organized cluster of thunderstorms.
   2. A cluster of wildfires burning in the same vicinity.

      The fire complex began as two separate fires.

      • 2020 September 16, “Millions of acres burn in California as weather improves in Northwest.”, in The New York Times, retrieved 16 September 2020:

        As of early Wednesday, there were at least 25 major wildfires and fire complexes, the term given to multiple fires in a single geographic area, burning in California, Christine McMorrow, a Cal Fire information officer, said.

   3. (taxonomy) A group of closely related species, often distinguished only with difficulty by traditional morphological methods.

      Synonyms: species complex, species group, species aggregate

      Hyponyms: species flock, superspecies

      • 2015 November 26, Mosè Manni et al., “Relevant genetic differentiation among Brazilian populations of Anastrepha fraterculus (Diptera, Tephritidae)”, in ZooKeys, volume 540, →DOI:

        Since then, a good deal of research has documented and concluded that the nominal species A. fraterculus actually comprises an unresolved complex of cryptic species.

5. (psychology) A group of emotionally charged ideas or mental factors, unconsciously associated by the individual with a particular subject, arising from repressed instincts, fears, or desires and often resulting in mental abnormality.

   Synonym: constellation

   Jim has a real complex about working for a woman boss.

   1. A fixed mental tendency or obsession.
6. (chemistry) A structure consisting of a central atom or molecule weakly connected to surrounding atoms or molecules, as for example coordination complexes in inorganic chemistry and protein complexes in biochemistry.
   • 2013 September-October, Katie L. Burke, “In the News”, in American Scientist:

     Oxygen levels on Earth skyrocketed 2.4 billion years ago, when cyanobacteria evolved photosynthesis: […] . The evolutionary precursor of photosynthesis is still under debate, and a new study sheds light. The critical component of the photosynthetic system is the “water-oxidizing complex”, made up of manganese atoms and a calcium atom.

7. (mathematics) A complex number.
   • 1996, Barry Simon, Representations of Finite and Compact Groups, page 50:

     The interesting aspect here is that U₃ is irreducible, even though all irreps over the complexes are one-dimensional because ℤ₄ is abelian.

8. (linguistics) A multimorphemic word, one with several parts, one with affixes.

complex (third-person singular simple present complexes, present participle complexing, simple past and past participle complexed)

1. (chemistry, intransitive) To form a complex with another substance.
2. (transitive) To complicate.

• “complex, n.”, in OED Online ⁠, Oxford: Oxford University Press, launched 2000.

• “complex”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.
• William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “complex”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.
• “complex”, in OneLook Dictionary Search.

Borrowed from Latin complexus.

• IPA^(key): (Central) [kumˈplɛks]
• IPA^(key): (Balearic, Valencia) [komˈplɛks]

• Audio (Barcelona):

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complex (feminine complexa, masculine plural complexos, feminine plural complexes)

1. complex (made up of multiple parts; composite; not simple)

   Synonym: compost

   Antonyms: simple, senzill

2. complex (complicated, not simple, easy or straightforward)

   Synonyms: complicat, embolicat

   Antonyms: simple, senzill

• nombre complex

• complexitat

complex m (plural complexos)

1. collection (a set of things or parts related to each other)
2. complex (e.g. of buildings)
3. (psychoanalysis, psychology, chemistry) complex
4. (mathematics) complex number, complex

• “complex”, in Diccionari de la llengua catalana [Dictionary of the Catalan Language] (in Catalan), second edition, Institute of Catalan Studies [Catalan: Institut d'Estudis Catalans], April 2007
• “complex”, in Gran Diccionari de la Llengua Catalana, Grup Enciclopèdia Catalana, 2025
• “complex” in Diccionari normatiu valencià, Acadèmia Valenciana de la Llengua.
• “complex” in Diccionari català-valencià-balear, Antoni Maria Alcover and Francesc de Borja Moll, 1962.

Borrowed from French complexe or German komplex, from Latin complexus.

• IPA^(key): /kɔmˈplɛks/

• Audio:

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• Hyphenation: com‧plex
• Rhymes: -ɛks

complex (comparative complexer, superlative meest complex or complext)

1. complex (composite)
2. complex (complicated)
3. (mathematics) complex (containing an imaginary component or involving imaginary numbers)

• → Indonesian: kompleks

complex n (plural complexen, diminutive complexje n)

1. complex (collection of buildings or facilities with a common purpose)
2. (psychoanalysis) complex (abnormal mental state caused by repression)

• → Indonesian: kompleks

complex (strong nominative masculine singular complexer, comparative complexer, superlative am complexesten)

1. Obsolete spelling of komplex which was deprecated in 1902 following the Second Orthographic Conference of 1901.
   • 1781, Immanuel Kant, “Die Diſciplin d. r. Vernunft in Beweiſen”, in Kritik der reinen Vernunft [Critique of Pure Reason], Riga: Johann Friedrich Hartknoch, page 785:

     Hiedurch nun, daß das Einfache in der Abſtraction vom Einfachen im Obiect ganz unterſchieden iſt und daß das Ich, welches im erſteren Verſtande gar keine Mannigfaltigkeit in ſich faßt, im zweiten, da es die Seele ſelbſt bedeutet, ein ſehr complexer Begriff ſeyn kan, nemlich ſehr vieles unter ſich zu enthalten und zu bezeichnen, entdecke ich einen Paralogism.

     (please add an English translation of this quotation)

From con- +‎ plicō.

• (Classical Latin) IPA^(key): [ˈkɔm.pɫɛks]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈkɔm.pleks]

complex (genitive complicis); third-declension one-termination adjective

1. closely connected, confederate, participant
2. of the twelve Olympians (Jūnō, Vesta, Minerva, Cerēs, Dīana, Venus, Mārs, Mercurius, Jūpiter, Neptūnus, Vulcānus, Apollō)

   Synonym: cōnsēns

Third-declension one-termination adjective.

1. No direct connection to the English adjective complex, which is from Latin complexus with an etymologically related, yet different stem.
2. The twelve Olympians were also called dī complicēs.

complex m or f (genitive complicis); third declension

1. participant, confederate, accomplice

Third-declension noun.

• “complex”, in Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press
• "complices", in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• “complex”, in Gaffiot, Félix (1934), Dictionnaire illustré latin-français, Hachette.

Borrowed from French complexe, from Latin complexus.

• IPA^(key): [komˈpleks]

complex m or n (feminine singular complexă, masculine plural complecși, feminine/neuter plural complexe)

1. complex

   Antonym: simplu

• complexitate

• “complex”, in DEX online—Dicționare ale limbii române (Dictionaries of the Romanian language) (in Romanian), 2004–2025