Definition of complex in English:



  • 1Consisting of many different and connected parts.

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

    • ‘The same notions can be extended to polynomial equations involving complex numbers.’
    • ‘Mathematicians find uses for complex numbers in solving equations.’
    • ‘He also classified real and complex numbers into classes which are algebraically independent.’
    • ‘Bombelli was the first person to write down the rules for addition, subtraction and multiplication of complex numbers.’
    • ‘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.

    ‘in naming complex ions, the names of the ligands are cited first’
    • ‘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.’
    • ‘There are, as you would expect from the simplicity of the alcohol molecule, no complex hydrocarbons emitted.’


  • 1A group or system of different things that are linked in a close or complicated way; a network.

    ‘a complex of mountain roads’
    • ‘The result is that we see her not in a single emotion, but a complex of emotions.’
    • ‘The ‘self’ is a complex of memories, thoughts, beliefs, desires etc. all of which can be doubted.’
    • ‘‘Network’ includes a complex of interconnected computer or communication systems of any type.’
    • ‘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.’
    • ‘It is part of a complex of closely related gull species that interbreed readily.’
    • ‘The complex of field systems and large stone walls extend from the north western slopes of Mount Brandon to within the boundaries of Dingle.’
    • ‘Rather than being a single disease, it is in fact a complex of related diseases which include forms known as yellow mosaic and veinbanding.’
    • ‘Eventually, of course, they run into other such complexes expanding from different kernels.’
    • ‘Structural studies revealed that cullin serves as a bridge to bring together different components of the complex.’
    • ‘The wheel itself was split into many different complexes.’
    • ‘The problem is not how to choose between two possibilities, but how to relate and weigh a complex of motives.’
    • ‘It has been argued recently that the mind is a complex of conflicting and complementary memetic patterns seeking to reproduce.’
    network, system, interconnected scheme, interconnected structure, interconnected system, nexus, web, tissue
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    1. 1.1A group of similar buildings or facilities on the same site.
      ‘a leisure complex’
      ‘a complex of hotels’
      • ‘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.’
      • ‘The company has expertise in building apartment buildings, shopping malls and office complexes.’
      • ‘These especially go well in complexes and office buildings that have an architectural importance.’
      • ‘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.’
      • ‘About 70 families were left homeless by the fire, which destroyed three buildings in the apartment complex.’
      • ‘They are normally installed with automatic closing devices in multiple residence buildings such as apartment complexes.’
      • ‘Developments vary from apartment blocks and hotels to modern luxury complexes with swimming pools, solariums, restaurants and a host of other facilities.’
      • ‘No one in their right mind would live here among the burned-out office buildings and development complexes.’
      • ‘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.’
      • ‘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.’
      • ‘Dentists' offices, doctors' offices and markets were all built into the apartment complexes to make life more efficient.’
      • ‘Massive corporate campuses, large and numerous residential complexes and modern retail facilities have come up along this belt.’
      • ‘The rehearsal room was a dilapidated building in a hospital complex.’
      • ‘Through its connecting walkways, a person could potentially live inside the buildings forever, navigating the maze between apartment complexes, office towers and malls.’
      • ‘We had the devil of a time running the cable through the conduits which were built into the apartment complex I live in.’
      • ‘Fires at the base of the complex of seven office buildings sent heavy smoke throughout.’
      • ‘Plans for building museums in the complex have also been made.’
      • ‘Usually, such mock drills are only conducted in high-rise buildings and in shopping complexes, but they are essential also in slum areas.’
      • ‘Mr Young said despite rumours he has no plans to build an apartment complex on the site.’
      building, structure, development
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  • 2Psychiatry
    A related group of repressed or partly repressed emotionally significant ideas which cause psychic conflict leading to abnormal mental states or behaviour.

    • ‘Like Jack, David had a complex and conflicted history of diagnoses, treatments and medication.’
    • ‘Jung, Freud and comrades helped to systematise intuitive skill while deciphering some psychic complexes of their own Europe in turmoil.’
    • ‘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.’
    • ‘The dark abyss of the mind and its complexes and obsessions must be conquered.’
    • ‘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.’
    1. 2.1informal A strong or disproportionate concern or anxiety about something.
      ‘there's no point having a complex about losing your hair’
      • ‘Every minor flaw gets magnified and many even develop a complex about it.’
      • ‘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.’
      • ‘I had such a complex about it that I never noticed that I was actually quite fair compared to everyone in the class.’
      • ‘But for the first time, many Americans were sophisticated enough to have developed a cultural inferiority complex.’
      • ‘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.’
      • ‘He was also a bookworm who had a complex about his family's poverty and a fan of kung fu and violent movies.’
      • ‘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.’
      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.

    ‘two guanine bases can attach themselves to the same platinum atom, forming a stable complex’
    • ‘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.’
    • ‘It correctly accounts for the structures of most covalent compounds of elements other than transition metal complexes.’
    • ‘Dyson and Welton used water and ionic liquid soluble organometallic clusters and complexes to catalyse hydrogenation of the aromatics.’
    1. 3.1Any loosely bonded species formed by the association of two molecules.
      ‘cross-linked protein–DNA complexes’
      • ‘It is not, however, clear whether association of ternary complexes is necessary to confer photoactivity, for instance by a stabilization effect.’
      • ‘Recently two checkpoint sensor protein complexes have been shown to bind damaged DNA.’
      • ‘This clearly suggests that the newly formed species may correspond to complexes of PEI with heparin.’
      • ‘The chromo-domain and the related chromo-shadow domain mediate the formation of protein complexes and their association with chromatin.’
      • ‘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’
    • ‘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.’
    • ‘Chloride is complexed with the silver chromate and fixed in a circular pattern around the entry point.’
    • ‘Several membrane protein structures have been solved in which the protein is complexed with a specific lipid.’
    • ‘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.’


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.