Definition of complex in English:



  • 1Consisting of many different and connected parts.

    ‘a complex network of water channels’
    • ‘Organisms such as fungi have evolved complex networks in which there are centralised and decentralised pathways to move nutrients around.’
    • ‘Twins can be joined by the head, chest and pelvis, sometimes sharing organs and a complex network of blood vessels.’
    • ‘Inside, a skylit atrium runs the full length of the building, connecting its richly complex spaces.’
    • ‘In Streedagh's sandhills, there lies a vast and complex network of rabbit burrows.’
    • ‘There is a complex network of channels and what look like highways that have been laid out in a massive organized fashion.’
    • ‘It was fascinating how Mr Fox so quickly constructed that complex network of tunnels.’
    • ‘For me, there is a complex network of paths through the house, all centering on the study where my current project is available for instant scrutiny.’
    • ‘The plant's shoots receive nourishment from a complex network of connections to the roots.’
    • ‘The condition is caused by damage to the complex network of nerves in the neck and shoulder when her arm became stuck behind her mother's pelvic bone during birth.’
    • ‘The impression one has when looking at maps of large-scale structure is that of a vast cosmic web, a complex network of intersecting chains and sheets.’
    • ‘As the vocal folds consist of a complex web of different muscle fibres, the tension and density of vocal folds can vary considerably.’
    • ‘Because of this, the structure of these converters are quite complex although easy to understand.’
    • ‘Keeping these elements in articulation as they move in different planes requires a complex joint.’
    • ‘Accounting for new irreducibly complex structures by the foregoing mechanisms is a completely different proposition.’
    • ‘It claims that the financial proceeds of organised crime are used, via a complex network of intermediaries, to buy the company's cigarettes.’
    • ‘The hips, on the other hand, are a very large and complex joint with many different muscles and attachments.’
    • ‘To reduce the harmful effects of exposure to DNA-damaging agents, the human genome has evolved a complex network of genome stability pathways.’
    • ‘Three geostationary satellites and a complex network of ground stations will carry out the task.’
    • ‘The complex wiring of old networks are gradually being replaced by a cleaner wireless environment.’
    • ‘The vehicle has four wheels all connected by complex machinery that simple minds like ours can't begin to describe.’
    compound, composite, compounded, multiplex
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    1. 1.1Not easy to analyze or understand; complicated or intricate.
      ‘a complex personality’
      ‘the situation is more complex than it appears’
      • ‘It is an enormously complex and difficult problem that defies easy solution.’
      • ‘Miller's writing is excellent, and he makes some rather complex biochemistry easy to understand.’
      • ‘Most studies also do not take into account the complex interplay between different variables in predicting lung volumes.’
      • ‘However, the wider international situation is increasingly complex.’
      • ‘Given these highly complex interactions, research in this area frequently yields contradictory conclusions.’
      • ‘He was all about clarity, making sure people could understand complex stories.’
      • ‘Features of financial products are becoming far too complex for the common man.’
      • ‘Traffic flow is an extremely complex phenomenon and its complete understanding is quite difficult.’
      • ‘Web services are fine, until you start to deal with complex data structures across different platforms.’
      • ‘The complex work involved intricate scheduling with cleanup crews and keeping myriad utilities happy.’
      • ‘His files are protected by a very complex system of coding and firewalls.’
      • ‘As I have noted a number of times, this is a highly complex issue.’
      • ‘In our highly divided and partisan political system, people tend to lack the ability to understand a complex reality.’
      • ‘However, the whole matter of indirect tax liability is devilishly complex and difficult to understand.’
      • ‘Reaching political consensus on such complex issues is never easy, given the diversity of interests that must be addressed.’
      • ‘The British press and wire services carried a far different and more complex story.’
      • ‘In other words, the problems are much more complex than Mr. Baker understands or cares to discuss.’
      • ‘Aging is an intricate, complex process that involves many areas of your body.’
      • ‘They need time to formulate complex thoughts in an easy language.’
      • ‘This chapter is written in a clear, understandable style, making it easier to understand the complex legal issues discussed.’
      complicated, involved, intricate, convoluted, tangled, elaborate, serpentine, labyrinthine, tortuous, impenetrable, byzantine, daedalian, gordian
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  • 2Mathematics
    Denoting or involving numbers or quantities containing both a real and an imaginary part.

    • ‘Bombelli was the first person to write down the rules for addition, subtraction and multiplication of complex numbers.’
    • ‘He also classified real and complex numbers into classes which are algebraically independent.’
    • ‘The same notions can be extended to polynomial equations involving complex numbers.’
    • ‘Mathematicians find uses for complex numbers in solving equations.’
    • ‘In addition to his work on geometry, Bolyai developed a rigorous geometric concept of complex numbers as ordered pairs of real numbers.’
  • 3Chemistry
    Denoting an ion or molecule in which one or more groups are linked to a metal atom by coordinate bonds.

    • ‘There are, as you would expect from the simplicity of the alcohol molecule, no complex hydrocarbons emitted.’
    • ‘Often the atoms comprising a complex molecule can be arranged in several ways and still satisfy the octet rule for each atom.’
    • ‘This process occurs when oxygen atoms bond to an iron atom at the center of a complex protein molecule known as oxyhemoglobin.’
    • ‘Biological processes, in turn, depend on the chemistry of complex molecules.’
    • ‘Carbohydrates can form more complex molecules when linked with other molecules.’


  • 1A group of similar buildings or facilities on the same site.

    ‘a new apartment complex’
    ‘a complex of hotels’
    • ‘He also expressed concern over other violations by real estate developers, who took small lakes and swampy areas in the northern part of the city as development sites for housing complexes.’
    • ‘Usually, such mock drills are only conducted in high-rise buildings and in shopping complexes, but they are essential also in slum areas.’
    • ‘Fires at the base of the complex of seven office buildings sent heavy smoke throughout.’
    • ‘Through its connecting walkways, a person could potentially live inside the buildings forever, navigating the maze between apartment complexes, office towers and malls.’
    • ‘These especially go well in complexes and office buildings that have an architectural importance.’
    • ‘We had the devil of a time running the cable through the conduits which were built into the apartment complex I live in.’
    • ‘Placing large parking lots around buildings means office complexes usually sit in the middle of an island of heat which requires more air conditioning.’
    • ‘He has watched as new building complexes have risen over sites he knows contain more lost tombstones.’
    • ‘They are normally installed with automatic closing devices in multiple residence buildings such as apartment complexes.’
    • ‘Dentists' offices, doctors' offices and markets were all built into the apartment complexes to make life more efficient.’
    • ‘The rehearsal room was a dilapidated building in a hospital complex.’
    • ‘About 70 families were left homeless by the fire, which destroyed three buildings in the apartment complex.’
    • ‘An increasing number of workers on low incomes are moving out as reasonably priced housing is replaced by expensive apartment complexes and luxury residential developments.’
    • ‘Developments vary from apartment blocks and hotels to modern luxury complexes with swimming pools, solariums, restaurants and a host of other facilities.’
    • ‘Plans for building museums in the complex have also been made.’
    • ‘Mr Young said despite rumours he has no plans to build an apartment complex on the site.’
    • ‘Massive corporate campuses, large and numerous residential complexes and modern retail facilities have come up along this belt.’
    • ‘At a council planning meeting on Tuesday it was agreed to extend the uses of the building to include a business complex with conference facilities on the south of the site.’
    • ‘No one in their right mind would live here among the burned-out office buildings and development complexes.’
    • ‘The company has expertise in building apartment buildings, shopping malls and office complexes.’
    building, structure, development
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    1. 1.1A group or system of different things that are linked in a close or complicated way; a network.
      ‘a complex of mountain roads’
      • ‘Eventually, of course, they run into other such complexes expanding from different kernels.’
      • ‘I find that a day that starts with a smile often carries on that way and my day did just that in spite of solemn moments and an occasional sadness mixed together in a complex of emotions.’
      • ‘Rather than being a single disease, it is in fact a complex of related diseases which include forms known as yellow mosaic and veinbanding.’
      • ‘The wheel itself was split into many different complexes.’
      • ‘The ‘self’ is a complex of memories, thoughts, beliefs, desires etc. all of which can be doubted.’
      • ‘The problem is not how to choose between two possibilities, but how to relate and weigh a complex of motives.’
      • ‘The complex of field systems and large stone walls extend from the north western slopes of Mount Brandon to within the boundaries of Dingle.’
      • ‘It has been argued recently that the mind is a complex of conflicting and complementary memetic patterns seeking to reproduce.’
      • ‘The result is that we see her not in a single emotion, but a complex of emotions.’
      • ‘‘Network’ includes a complex of interconnected computer or communication systems of any type.’
      • ‘Structural studies revealed that cullin serves as a bridge to bring together different components of the complex.’
      • ‘It is part of a complex of closely related gull species that interbreed readily.’
      network, system, interconnected scheme, interconnected structure, interconnected system, nexus, web, tissue
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  • 2Psychiatry
    A related group of emotionally significant ideas that are completely or partly repressed and that cause psychic conflict leading to abnormal mental states or behavior.

    • ‘Jung, Freud and comrades helped to systematise intuitive skill while deciphering some psychic complexes of their own Europe in turmoil.’
    • ‘The dark abyss of the mind and its complexes and obsessions must be conquered.’
    • ‘I don't know if anyone has done any major writing comparing Jung's ideas of complexes and archetypes to electrical networks, but it would be a great thing to look into.’
    • ‘For about six to eight hours you seem to have no physical experience of the chronic muscular tensions that Reich says are symptomatic of unhealthy mental or emotional complexes.’
    • ‘Like Jack, David had a complex and conflicted history of diagnoses, treatments and medication.’
    1. 2.1informal A disproportionate concern or anxiety about something.
      ‘there's no point having a complex about losing your hair’
      • ‘He was also a bookworm who had a complex about his family's poverty and a fan of kung fu and violent movies.’
      • ‘Perhaps I should get a complex about the Jonah joke.’
      • ‘He brought all his phobias and complexes to his film-making and whatever ingrained attitudes he had about women were also hauled along.’
      • ‘Every minor flaw gets magnified and many even develop a complex about it.’
      • ‘I had such a complex about it that I never noticed that I was actually quite fair compared to everyone in the class.’
      • ‘I've been lucky that the men I've fallen in love with have fallen in love with me, so I've never had that complex about the way I look.’
      • ‘Since then, the girl had believed she was not photogenic and gradually developed an inferiority complex.’
      • ‘The threatening letters, believed to be fake by many, only accentuated the fear complex.’
      • ‘But for the first time, many Americans were sophisticated enough to have developed a cultural inferiority complex.’
      obsession, phobia, fixation, preoccupation
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  • 3Chemistry
    An ion or molecule in which one or more groups are linked to a metal atom by coordinate bonds.

    • ‘Dyson and Welton used water and ionic liquid soluble organometallic clusters and complexes to catalyse hydrogenation of the aromatics.’
    • ‘It correctly accounts for the structures of most covalent compounds of elements other than transition metal complexes.’
    • ‘If two molecules or complexes have the same molecular formula they are candidates for stereochemical analysis.’
    • ‘Metal complexes are generally prepared by reacting a salt with another molecule or ion.’
    • ‘It is known that metal cations form complexes with anionic phosphodiester groups and carbonyl oxygens in the glycerol backbone of phosphocholine lipids.’
    1. 3.1Any loosely bonded species formed by the association of two molecules.
      ‘cross-linked protein-DNA complexes’
      • ‘Recently two checkpoint sensor protein complexes have been shown to bind damaged DNA.’
      • ‘It is not, however, clear whether association of ternary complexes is necessary to confer photoactivity, for instance by a stabilization effect.’
      • ‘The chromo-domain and the related chromo-shadow domain mediate the formation of protein complexes and their association with chromatin.’
      • ‘This clearly suggests that the newly formed species may correspond to complexes of PEI with heparin.’
      • ‘This might occur in newly synthesized proteins to aid in folding or in mature proteins to control their activity or association with other protein complexes.’


[WITH OBJECT]Chemistry
  • Make (an atom or compound) form a complex with another.

    ‘the DNA was complexed with the nuclear extract’
    ‘the complexed metal ion’
    • ‘Chloride is complexed with the silver chromate and fixed in a circular pattern around the entry point.’
    • ‘They may reduce mineral metal ions through direct contact or by reducing complexed ions.’
    • ‘Iron is mostly complexed with the organic ligands or colloids that are very abundant in natural seawater.’
    • ‘However, as mammalian cells will not readily take up naked nucleic acids, the RNAs have to be complexed with agents such as cationic lipids to allow them to enter the cells.’
    • ‘Several membrane protein structures have been solved in which the protein is complexed with a specific lipid.’


Mid 17th century (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.