Definition of factor in US English:



  • 1A circumstance, fact, or influence that contributes to a result or outcome.

    ‘she worked fast, conscious of the time factor’
    ‘his legal problems were not a factor in his decision’
    • ‘School may not be the number one source of stress for everyone, but it certainly is a contributing factor in most cases.’
    • ‘The small sample size was obviously a confounding factor in interpreting the results.’
    • ‘However, on hearing evidence and viewing a security video taken at the scene, she said the restraint used had been a contributory factor in his death.’
    • ‘Timely administration is a key factor in achieving positive results with hyaluronidase.’
    • ‘From the point of conception onwards, parents are now viewed as a risk factor in their children's lives.’
    • ‘The safety campaigners point out that speed is a contributory factor in more than 1,100 deaths on Britain's roads every year.’
    • ‘Obesity is a risk factor in diabetes, heart disease, renal failure, joint problems and possibly cancer.’
    • ‘Similarly, family and friends of students have been considered an influential factor in choosing an agriculture major.’
    • ‘Make no mistake about it, circumstance is a key factor in whether a player lives up to expectations in this league.’
    • ‘She stresses that all mini-melon lines are the result of natural breeding and that genetics is probably the biggest factor in her results.’
    • ‘The excessive intake of food also puts a heavy burden on the pancreas and speeds the ageing process, which is a risk factor in diabetes.’
    • ‘What is the greatest factor in contributing to childhood obesity?’
    • ‘The National Safety Council says faulty vehicles are a contributory factor in just 1% of road accidents.’
    • ‘A key factor in the result was the large voter turnout, which ranged from 76 to 85 percent across the main electorates.’
    • ‘It is thought the bidders involved in the previous submission had built in a risk factor in case they lost money on the scheme, which meant the overall price went up.’
    • ‘The result will be a factor in his decision making.’
    • ‘While wet conditions have been cited as a contributing factor in the shaky landing, it's still too early to know what went wrong, said Armour.’
    • ‘A strong dynamic relationship with neighbouring Derry is a contributory factor in the Donegal town's elevation to city status.’
    • ‘Some scientists believe that a chronic shortage of dietary calcium is a contributing factor in developing osteoporosis.’
    • ‘Speed must have been a contributory factor in some or all the collisions on the stretch and at least 20 per cent of drivers on the road must exceed the speed limit.’
    element, part, component, ingredient, strand, constituent, point, detail, item, feature, facet, aspect, characteristic, consideration, influence, circumstance, thing, determinant
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    1. 1.1Biology A gene that determines a hereditary characteristic.
      ‘the Rhesus factor’
      • ‘These relationships among genes and transcription factors are the genetic regulatory network.’
      • ‘In related studies, the genetic factors determining the conformation of curd was analyzed.’
      • ‘These findings provide insights into how genomes and environmental factors interact to determine phenotypes.’
      • ‘However, it remains unclear what factors determine the rate of evolution of gene expression.’
      • ‘Homeobox genes encode transcription factors involved in many aspects of developmental processes.’
  • 2A number or quantity that when multiplied with another produces a given number or expression.

    • ‘Here, the change often seemed to be proportional to the molecular weight of the solute multiplied by a factor of two, three or four.’
    • ‘Take the maximum draw weight of the bow required and multiply this by a factor of 5.’
    • ‘Multiply your X factor by 159 to reach a daily total of 2,067 calories a day.’
    • ‘A meter is the basic unit of length but shorter and longer units are obtained by multiplication by factors of ten.’
    • ‘The micropipette diameter was also measured, and the value multiplied by a factor of 0.92.’
    1. 2.1Mathematics A number or algebraic expression by which another is exactly divisible.
      • ‘A number that only has two factors, one and itself, is called a prime number.’
      • ‘The fraction 10/12 can be reduced, because both the numerator and denominator have factors of 2.’
      • ‘So what about those Fibonacci numbers with no factors (apart from 1 and itself, of course)?’
  • 3Physiology
    Any of a number of substances in the blood, mostly identified by numerals, which are involved in coagulation.

    • ‘Supplying a blood coagulation factor through transfusion is the main treatment for the disease.’
    • ‘Coagulation factors circulate as zymogens and platelet procoagulant surfaces are internalized.’
    • ‘These include a change in the balance between procoagulant and anticoagulant factors in the blood.’
    • ‘In hemostasis, there is a balance between procoagulant factors and natural anticoagulant proteins.’
    • ‘In recent years literature is emerging on the role of different factors of blood coagulation in arterial thrombosis.’
  • 4A business agent; a merchant buying and selling on commission.

    • ‘Each district was normally headed by a chief factor, who reported to the departmental governor.’
    • ‘The brassfounders' traditional use of factors and agents accounts for the maddening anonymity of the catalogues.’
    agent, representative, deputy, middleman, intermediary, go-between
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    1. 4.1 A company that buys a manufacturer's invoices at a discount and takes responsibility for collecting the payments due on them.
      • ‘Usually notice is given to the account debtor and the debts are collected directly by the factor.’
      • ‘It is the factor who then receives payment from the importer.’
    2. 4.2archaic An agent, deputy, or representative.
      • ‘Now a gentleman called Antigono happened to arrive in Paphos on business; he was of a great age and of greater wisdom but of only modest wealth, for he had acted in a number of transactions as factor to the King of Cyprus but luck had gone against him.’
      • ‘This was the official report of the expedition that Biedma, as factor to the king, wrote to the "King of Spain in Council".’


[with object]
  • 1Mathematics

    another term for factorize
    • ‘I don't understand how to start out factoring this algebra.’
    • ‘Is there some way of identifying whether a number has an odd or even number of distinct prime factors without factoring?’
    • ‘It meant that the resources needed to use previously known algorithms for factoring numbers of a given size could now be used to factor significantly larger numbers.’
    • ‘But if you could factor large numbers then you could break these codes.’
    • ‘Every positive integer can be factored into the product of prime numbers, and there's only one way to do it for every number.’
  • 2Sell (one's receivable debts) to a factor.

    • ‘It also includes other facilities with specific purposes such as leasing of fixed assets, factoring and invoice discounting.’
    • ‘Thus in block discounting and factoring the trader sells the debts due to him from his customers to his financier at a discount.’
    • ‘Of considerably more importance is that Scanchem is now factoring its invoices, and thus increasing its apparent borrowing, the outstanding amounts being secured by a charge on the book debts of the company, as is normal.’
    • ‘They were however concerned that they might be factoring bogus invoices.’
    • ‘Consider factoring or invoice discounting - drawing down bank finance against your debtor balance.’


  • the — factor

    • Used to indicate that something specified will have a powerful, though unpredictable, influence on a result or outcome.

      ‘the feel-good factor’
      • ‘It should be an interesting race with the key factor being the influence of temperature on both makes of tyres.’
      • ‘Such an understanding should be the guiding factor in our attempts to weed out corruption.’
      • ‘When power or greed is the motivating factor, the result can be disastrous.’
      • ‘The number of injuries this season has been the major factor in the team's poor results.’
      • ‘Good sports and leisure facilities are a keystone in the feel-good factor of any area.’
      • ‘This is what you might call the feel-good factor or the pleasure principle.’
      • ‘The ambience alone was the saving factor, and luckily the food turned out to be wonderful.’
      • ‘He believes that the impact you create on society should be the defining factor.’
      • ‘This appears to have been the primary factor influencing the majority opinions in White v Jones.’
      • ‘Tracing back their lives, the survey found that in almost every case the decisive factor had been marriage.’

Phrasal Verbs

  • factor something in (or out)

    • Include (or exclude) something as a relevant element when making a calculation or decision.

      ‘when the psychological costs are factored in, a different picture will emerge’
      • ‘The Department of Education had estimated the bill for compensation would reach €508m, rising to €610m when legal and administration costs were factored in.’
      • ‘After capital gains are factored in, home owners made a gain of £5,000, which he says shows that it remains overwhelmingly advantageous to buy rather than to rent.’
      • ‘Air conditioning costs are factored out, so the drop isn't a reflection of the cooler spring.’
      • ‘Every time we hear of an interest rate hike, people at home, consumers, people like you and me, want to know how does that affect us, and how long before the hike is factored in?’
      • ‘Courts Service chief executive officer PJ Fitzpatrick said they did not see the original lease until much later and were unaware refurbishment costs were factored in to the rental price.’
      • ‘Puppeteers argue their fees are low if their working hours are factored in, including preparation for the show and the cleanup.’
      • ‘This figure holds after many other influences are factored out.’
      • ‘When anxieties, other fears and sleep disturbances were factored in, the prevalence of depression among all women increased to about 16%.’
      • ‘He estimates the budget at $20,000 in cash and donations, and well over ten times that much if actor, location, music, and crew contributions are factored in.’
      • ‘Union officials estimated that when factors such as the cost of health benefits were factored in, the company's proposal amounted to a 40 cent per hour pay cut.’


Late Middle English (meaning ‘doer’, also in the Scots sense ‘agent’): from French facteur or Latin factor, from fact- ‘done’, from the verb facere.