Definition of duplicate in English:



  • 1Exactly like something else, especially through having been copied.

    ‘a duplicate set of keys’
    • ‘They were duplicate copies that the commission had.’
    • ‘For example, I never realised you should keep duplicate copies of receipts.’
    • ‘And beyond duplicate copies, we just don't have that much space here anyway!’
    • ‘Drivers seeking a duplicate licence have to go to their local Garda station with photographic identification and their social security number and have a D800 form signed by a member.’
    • ‘The fee for a duplicate renewal license shall be $5.’
    • ‘She suggested that in the morning I try to find a license bureau and obtain a duplicate license.’
    • ‘They then applied for a driver's permit with his name but their photo. taking everything that they had gotten they walked into a dealer and ordered a duplicate key for the car.’
    • ‘It addressed the issue of duplicate entries and excess paperwork, instead allowing for immediate on site recording of all maintenance work.’
    • ‘Last year the locks on all 164 rooms at the hotel had to be changed after an armed gang escaped with a bag of duplicate card keys.’
    • ‘Deepening the mystery are police claims the raid was carried out by someone who had a duplicate key.’
    • ‘Then I staggered home and gave up my duplicate keys.’
    • ‘They were strongly suspicious the motorbike had been stolen by the rental operator who obviously knew their temporary address and had a duplicate key.’
    • ‘Still, we wondered, why couldn't the server recognize duplicate keys, and just refuse the installation?’
    • ‘Maintenance of the service numbers and the civilian numbers is not consistent with this aim and is a problem where duplicate numbers have been issued.’
    • ‘Nora makes duplicate keys for whoever asks and encourages them to walk right in whenever they please.’
    • ‘The government will issue a new or duplicate number to the name on the certificate.’
    • ‘Based upon analysis of duplicate samples, reproducibility was better than 3% of the measured concentration of each element.’
    • ‘In many cases, only the locksmith who installed the original system can make duplicate keys.’
    • ‘At the very least, you should make an extra copy of your most vital data on duplicate media and store it off-site.’
    • ‘We deleted duplicate hospital records by retaining only one copy of events characterised as the same admission for the same patient on the same day.’
    matching, identical, twin, corresponding, equivalent
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  • 2technical Having two corresponding or identical parts.

    ‘Basically, identical and duplicate infrastructure components serve the critical systems.’


  • 1One of two or more identical things.

    ‘books may be disposed of if they are duplicates’
    • ‘Now things are sorted, you should be able to identify duplicates, spares, and rubbish.’
    • ‘What you really need is some kind of weighted-sampling without replacement (which you can simulate by throwing out duplicates, but then you waste time trying to find a reasonable sample).’
    • ‘The pair were both head down reading duplicates of some glossy brochures.’
    • ‘Although 7,000 suspected users of ‘pay per view’ child porn sites based in the US were identified in Britain, police said the actual number would probably be lower, partly due to duplicates.’
    • ‘In a test, 41 duplicates were found in one month.’
    • ‘19 people nominated what I counted as 37 items, many of which were duplicates.’
    • ‘The site currently lists 76,210 stories written by 6,831 writers (although there are a few duplicates and errors).’
    • ‘I still need to sort through a little over half of that for duplicates, incomplete files, etc.’
    • ‘In addition, there is a quarterly auction through which members can sell their duplicates to other members.’
    • ‘He was kind enough to let me have some duplicates from his own collection.’
    • ‘Would it not make better sense to take a head count and track the duplicates?’
    • ‘People are using spam address lists they've got from somewhere because I get as many as ten duplicates of each item.’
    • ‘When she told this to the cameras she also announced to the audience that everyone would be getting a duplicate of the bath robe after the show.’
    • ‘It maintains only one copy of any attachment avoiding duplicates and wasted storage space.’
    • ‘The company received close to 10,000 inputs, even after going through the tedious process of screening duplicates.’
    • ‘The Civilian tiles are the set of tiles that have duplicates while the Military tiles are those that are unique.’
    • ‘Sort through drawers and cabinets, discarding duplicates, broken items and dust collectors.’
    • ‘Unlike so many suburban blocks where the homes are all duplicates of each other, set apart only by the gilded numbers hammered onto the garages, Sycamore is a hodgepodge of houses.’
    • ‘I'm mostly doing some much-needed maintenance on my archive files and backups: reorganizing folders, deleting duplicates, burning DVDs, that sort of thing.’
    • ‘For storage efficiency, e-mail can be compressed, duplicates removed and indexed for fast access.’
    exact likeness, mirror image, double, duplicate, carbon copy, replica, image, living image, lookalike, clone
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    1. 1.1A copy of an original.
      ‘locksmiths can make duplicates of most keys’
      • ‘Portraiture is an art unusually bedevilled by duplicates and copies.’
      • ‘Another similar statue was erected at the British Museum, and a duplicate of the statue was specially made in Britain and imported to sit by the new development.’
      • ‘A point-in-time copy represents an exact duplicate of a data volume at the moment the copy was created.’
      • ‘I have a house on a quarter acre in a south Dublin suburb with enough room to build a duplicate of the existing house in the side garden.’
      • ‘In fact, the specimens we used are isotypes; these represent duplicates of the first collections made of these two newly formed species.’
      • ‘The child had to choose the correct items from carefully crafted duplicates; items included spectacles, a pencil, a bowl, a walking stick and a small hand drum.’
      • ‘The images are duplicates of prints by the early 20 th-century French photographer already in the museum's collection.’
      • ‘But making a duplicate for a lost key needs more imagination.’
      • ‘All 10,000 patentees were contacted at their post offices of record and requested to lend the inventor's copy of their patents to the Patent Office so the copies could be duplicated and the duplicates placed in the files.’
      • ‘Why buy expensive plastic duplicates of what grows naturally in the garden?’
      • ‘It tells the story of residents of a small town who are replaced by inert duplicates, which are hatched from alien ‘pods.’’
      • ‘He has a secret duplicate of the key with which he is locked up at night.’
      • ‘There are several instances of singers themselves being offered duplicates instead of the original versions.’
      • ‘The doppelgänger trees were duplicates of the eight-taxon focus tree with sites evolving at the same rates but independently of that tree.’
      • ‘He said: ‘The lockmaker kept a copy of the keys in case one was ever lost and they needed to make a duplicate.’’
      • ‘I gave him the dog-tag, he makes duplicates, he sells them now, and that really broke my heart because this is something sacred to me that I gave the boy.’
      • ‘The duplicates were distributed to familiarise citizens with the new currency but police feel they could be exploited and have urged people to destroy them.’
      • ‘What if God were to collect the molecules sloughed off of my body and, during my lifetime, construct a duplicate of me from them: is it I, Lord?’
      • ‘Unfortunately, with time travel being so unreliable for humans, he can only create a cyborg duplicate of himself and trust that it gets the job done.’
      • ‘‘Yes, and here's yours,’ the Boss responds, handing me a duplicate of my current ID card.’
      copy, carbon copy, carbon, photocopy, facsimile, mimeo, mimeograph, reprint
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  • 2

    ‘The method of doing this comparison varies according to what kind of duplicate is being played.’
  • 3archaic A pawnbroker's ticket.

    ‘And then you got another ticket, called the duplicate, with the date changed and another stamp on it.’


[with object]
  • 1Make or be an exact copy of.

    ‘information sheets had to be typed and duplicated’
    ‘they have not been able to duplicate his successes’
    • ‘Simply, we're now able to copy an atom, duplicating everything about it except its position and velocity in a new atom somewhere else.’
    • ‘I have taken pictures in rain and snow and duplicated exact copies of this same type of picture in the past for experimentation purposes.’
    • ‘More likely, they thought they could duplicate the Spain success.’
    • ‘Don't try to duplicate someone else's success.’
    • ‘No sooner had the last drop of champagne been poured in Miami than other small-market teams began to wonder if they could duplicate the Marlins' success.’
    • ‘Nearly from the beginning of his bodybuilding career, people have followed his path, hoping to duplicate some of his success.’
    • ‘Oh yeah, you may scoff but soon you'll be copying my pink eye look and trying to duplicate my Gabriel's trumpet-like sneeze.’
    • ‘The first question to answer is whether your business success can be easily duplicated by someone else.’
    • ‘It takes about 20 minutes to cook on the griddle, arrives piping hot, and is covered in a tasty Japanese sauce I haven't been able to duplicate at home.’
    • ‘Thus the band is left with studio recordings that are almost impossible to duplicate onstage.’
    • ‘However, by its very nature that quality cannot be duplicated though sometimes I was able to adapt it and make it my own.’
    • ‘It is impossible for us now to duplicate the Great Pyramid even if every country's resources and a trillion dollars were spent on the project.’
    • ‘But the weather combined with the intensely chalky soil yields a sparkling wine that is impossible to duplicate in many New or Old World climates.’
    • ‘With the ever increasing security gate access codes had become nearly impossible to duplicate, but with the warp drive they didn't even have to try.’
    • ‘Since he has never been able to duplicate that condition, that tells me he does not have a game plan for achieving it - that it was luck.’
    • ‘The key to franchise success is being able to duplicate what someone else has already successfully done.’
    • ‘You can even maintain balance in positions impossible to duplicate with free weights.’
    • ‘Some of these make the most of the new medium, and would be impossible to duplicate in the print world.’
    • ‘If the trees were properly priced to reflect this value or if the logging company was responsible for duplicating all of the services that the trees previously provided, it simply would not be economically smart to cut them all down.’
    • ‘Copycat journalists amplified this dubious academic research by claiming that teenage murderers were duplicating their favourite violent scenes.’
    copy, photocopy, photostat, xerox, mimeograph, make a photocopy of, take a photocopy of, make a carbon copy of, make a carbon of, make a facsimile of, reproduce, replicate, reprint, run off
    repeat, do over again, do again, redo, perform again, replicate
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    1. 1.1Multiply by two; double.
      ‘the normal amount of DNA has been duplicated thousands of times’
    2. 1.2Do (something) again unnecessarily.
      ‘most of these proposals duplicated work already done’
      • ‘Now the president is saying, oh, well, we might give you tax relief if you will sign on to my prescription drug proposal, which duplicates coverage that's already provided.’
      • ‘Research that duplicates other work unnecessarily or which is not of sufficient quality to contribute something useful to existing knowledge is unethical’
      • ‘Alliances create better communities which tap into the strength of their multiple institutions and decrease unnecessarily duplicated resources.’
      • ‘First, we needed to ensure that all desired curricular outcomes were being addressed and that no outcomes were unnecessarily duplicated.’
      • ‘The bill would also force the earth to devote its full attention to absorbing carbon dioxide and other greenhouse gases, rather than duplicating products already available from the private sector, he added.’
      • ‘This duplicates a service already provided locally by councils and voluntary groups and is entirely unnecessary.’
      • ‘Is it the duty of an already stretched institution to duplicate the role of common rooms, to cut back the funding to its essential political role, and seek to maintain an unwieldy sabbatical structure?’
      • ‘He said the exercise would not duplicate routine examinations already carried out by the District Auditor, Audit Commission and the Social Services Inspectorate.’
      • ‘But he believes the project will simply duplicate work that police already carry out and says the money would be better spent on the street than on figures.’
      • ‘The Fund's monies will be spent over a three-year period and will not duplicate existing services already provided by the Home Office.’
      • ‘We begin by doing a community profile to assess what the needs are in the area, because it's important not to duplicate services that already exist.’
      • ‘He denied it was duplicating work already being done by Hull Council, or repeating expensive studies done in the past.’
      • ‘In Norway the government has banned new medicine which duplicates medicine already in use, therefore drug companies have no incentive for using animal experiments to develop medicine which they cannot sell.’
      • ‘While informative, there are many gaps when there is no information and a few times the text duplicates things already stated in the audio commentary.’
      • ‘The center gets involved only if all significantly affected parties agree to its presence, and tries not to duplicate services already available.’
      • ‘Others said a united relief committee would duplicate machinery already in existence and might lead to confusion.’
      • ‘Personally I couldn't care less about trying to duplicate effects that have already been achieved using the arcane language of electronics.’
      • ‘Some of the capacity indicators duplicate measurements already used elsewhere in the ESI.’
      • ‘If the requirement duplicates a condition already satisfied, it imposes a double burden on the provider of a service, and it therefore cannot be justified.’
      • ‘To the extent that civil unions will duplicate marriage, then extending that privilege is clearly unnecessary.’


    in duplicate
    • 1Twice in exactly the same way.

      • ‘Each DNA specimen was analyzed at least twice in duplicate.’
      • ‘The experiment was performed at least twice in duplicate.’
      • ‘The screen was performed in duplicate and repeated twice, and mutants common to both screens were characterized further.’
      • ‘All samples were run in duplicate and the results were expressed as HIV RNA copies/ml.’
      • ‘Experiments were done in duplicate and a comparison of duplicates showed good agreement.’
      • ‘Each sample was analyzed in duplicate, and the means of the duplicates served as data.’
      • ‘Eight commercially available clones containing intergenic regions from the yeast genome were used in duplicate as hybridization and data analysis controls.’
      • ‘The quantitative pilocarpine iontophoresis tests were performed with measurements of sweat weight and chloride concentrations in duplicate, with sweat specimens being collected concurrently from the right and left arm.’
      • ‘Within an experiment, all strains were grown in duplicate at each pheromone concentration and plates were randomly distributed in a sealed plastic Tupperware container with a moist paper towel to prevent drying of the small plates.’
      • ‘A dilution series of each experimental sample was generated and run in duplicate.’
      1. 1.1Consisting of two exact copies.
        ‘forms to complete in duplicate’
        • ‘Take note that this was in duplicate, with color, too - there were some parts which had to be in red font.’
        • ‘With a changed political topography, all major public buildings - museums and opera house - were now in duplicate.’
        • ‘The Application for licensing as a Customs and Excise bonded warehouse should be made on the letterhead of the applicant in duplicate and addressed to the Commissioner for Customs and Excise.’
        • ‘‘The only difference is that paper tickets are printed out in duplicate, whilst e-tickets are stored safely in our computer system,’ she said.’


Late Middle English (in the sense ‘having two corresponding parts’): from Latin duplicat- ‘doubled’, from the verb duplicare, from duplic- ‘twofold’ (see duplex).