What's the difference between "replication" and "duplication"?

According to Cambridge dictionary:

duplication (n): the act or process of making an exact copy of something.

replicate (v. but the same definition for noun): to make or do something again in exactly the same way.

I really don't find any difference between them in the following context for example: when having two keys that they're really the same 100%. The can I say "These keys are duplications / replications".

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    See here english.stackexchange.com/questions/68920/…
    – Eddie Kal
    Commented May 4, 2018 at 3:03
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    In database technology, replication is a repeated activity where as duplication is a one time event. I want to replicate table A on server 1 to Server 2 table A continuously. so if server1.tableA changes values so does Server2.TableA. Duplication means I create server1.tableA once on Server2.TableA. And as Server1.TableA changes, Server2.TableA does not and get out of sync. So I guess it would be dependent on the context in which the words are used. Replication is repetitive/scheduled event, duplication is a one time
    – xQbert
    Commented May 4, 2018 at 18:34
  • When the US Bureau of Printing and Engraving prints money, that's replication. When I stick a $20 bill on the Xerox machine and make a copy, that's duplication.
    – Hot Licks
    Commented May 4, 2018 at 21:45

6 Answers 6


When you replicate something, you get a copy that's almost the same as the original, but not quite the same. There is usually some sort of difference between the original and the replicate. The original and its copy can have different sizes, for example. But the most important difference between the two is their identity—the original and its copy are not going to be the same thing at least in terms of their identity! An example that illustrates this best would be a replica of a famous painting. A professional painter can make an exact replica of the Mona Lisa. Even though the two paintings look exactly the same, we all agree that there is still a big difference between the two paintings! The original costs millions of dollars because it's the original work of Leonardo da Vinci and the replica is just a mere copy of it. So, the idea behind replication is that the replicate is always slightly different from the original at least in terms of its identity.

As for the other term, the result of the process of duplication is a duplicate which is an identical copy of the original in all of its aspects. If you make a duplicate of the keys to your house, the duplicate is going to be absolutely identical to the original keys in all respects. This means that a duplicate of something is as good as the original and can be used to replace it completely while this is usually not true for replicates.

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    I used my intuition. Commented May 4, 2018 at 3:38
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    @subtle_sibling: This is too similar for me to post my own answer, but I think it might help clarify this answer: A "duplicate" is something that can replace the original, whereas a "replica" is something that could be used as a representation of the original. In the case of DNA, so I suppose it could be argued that the replica of the DNA could never replace the original; it could only be used as a representation of it.
    – user541686
    Commented May 4, 2018 at 8:54
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    DNA replication introduces errors. Commented May 4, 2018 at 10:31
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    @dan You would most definitely say 'replicate,' never 'duplicate' in that context, at least according to my native-English and many-years-of-IT instincts. I find it difficult to say why, but the idea that you can't use 'duplicate' for something that might be an imperfect copy sounds plausible. (However, I think if you wanted to generate a new entry in your issue tracker with a different number but everything else the same, you would 'duplicate' the issue, much as one clicks 'duplicate' in a tab menu in Chrome to get another tab with the same contents and history.)
    – cjs
    Commented May 4, 2018 at 11:47
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    I disagree with the reasoning that you can determine which is which by the outcome alone. Replication can produce identical results.
    – Astralbee
    Commented May 4, 2018 at 13:25

Though they mean the same, they are not always interchangeable. You need to study the context before using those words as synonyms to each other.

Say, for example, if there is a group of scientists and they are trying to do an experiment that has been previously attempted by someone else, they try to replicate the results. The word 'duplicate' doesn't go there!

If I'm a good painter, I can replicate the Mona Lisa, I cannot 'duplicate' it! So, to answer this question, check twice before interchanging these words.

Likewise, when you lose your original driving license or any other document, you apply for a duplicate copy. There, 'replica' does not work!

  • Thank you for the answer. So if there are a lot of context how should I know in what case to use this one or this one? Is there no a rule when to use one of them? Commented May 4, 2018 at 2:36
  • @subtle_sibling you need to use your horse sense. Read more.. and you'll identify what goes where. For instance, a duplicate key is widely used. Seldom you may come across a 'replica' of a key unless the key is terrifically unique or has a historical value.
    – Maulik V
    Commented May 4, 2018 at 5:15
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    Agreed. In science, replicate measurements are different measurements of what is supposedly the same thing. The main point is that they do often differ at least slightly in practice; the aim of replication is to get a handle on that variability, whether it is measurement error and/or some other kind of uncontrolled variability. In contrast, duplicates in data are exact copies of records (e.g. for individual people). Sometimes, important data are keyed in twice, and so there should be identical copies. But duplicates in this sense could also mean three or more identical records.
    – Nick Cox
    Commented May 4, 2018 at 10:18
  • These rules aren't hard and fast, though. Here is someone using "duplicate" in the context of research, for example. Commented May 4, 2018 at 10:33
  • Well, as far as driver's licenses go, applying for a duplicate is expensive and slow in some countries, so you might be better off asking a forger to make a replica for you.
    – cjs
    Commented May 4, 2018 at 11:52

In addition to the answers above, I would add that a duplicate mostly apply to objects, like an ID card duplicate in case of loss or damage, a line in a source code, a photocopy of a document...

The noun replicate was already stated by previous answers, but now, let's consider the verb to replicate

Consider a crime scene witnessed by someone. When asked from the police, the witness may for example replicate the gestures of the murderer to describe how the scene went. In this context, it is more like mimics, trying to be as close as possible to the original action.

Now, consider software engineering. The tester tells the programmer that there is a bug on the X module. The programmer tests the module but is unable to find out what manipulations the tester did in order to the bug to occur. He then calls the tester to show him what he did step by step. The tester then replicates his actions and the bug is occuring again.

So, the verb to replicate may still infer copying something, but it could also be re-doing something, as the verb to duplicate is mostly making a copy of something.


It should be noted that replication and duplication technically refer to processes, not any result or object that results from such processes.

Previous answers refer to the end result to determine which process has been followed (replication or duplication); ie that a duplicate is normally an exact copy of an original (such as a photocopy of a paper) whereas a replica is not necessarily to the exact specifications or dimensions.

However if is important to note that while the processes of duplication and replication may be different, the end result from both can still be identical.

For example:
A computer programmer codes some software that produces a result.
Another programmer is asked to replicate that software.
The second programmer may use an entirely different method to achieve the same result.

However, in an entirely different example: if it is found that two people are performing the exact same task and the repetition of work is unnecessary, this is referred to as a duplication of work irregardless of whether the two are strictly following the same process, so there are clearly exceptions.

Finally, although the correct English terms for the results of duplication and replication would be duplicate and replica, it is not uncommon in colloquial speech to hear them referred to by their processes. Incorrect, but nevertheless sometimes used.

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    Your example, which seems correct, directly contracts the definitions given in the OP. Hmm. Commented May 4, 2018 at 16:07

In addition to the answers above, I get the impression that "duplication" generally refers to one duplicate copy (as opposed to triplicate), and sometimes a few (eg "I cut four duplicate keys from the original, and I still have the duplicate keys with me"), and the focus is more on the object being duplicated. So you may have a duplicate that you used a different process to produce, as long as they are identical in all ways that matter. A duplicate is also normally 1:1 scale to the original.

Whereas "replicate" seems to be more focused on the process and the result is the same or close to the same because you performed the same process, or at least you say you did (if its something you are selling to tourists). A replica may be scaled up or down from the original and still be called a replica (eg "He replicated his winning sales strategy from a small business beginning all the way up to a multi-million dollar company").

For instance You replicate old ships, not duplicate them: https://en.wikipedia.org/wiki/Ship_replica (though they seem to like calling significant scale changes "models" not replicas)

Anyway, my 5c worth, based on my understanding of usage in Australia, sailing and computer science.


Duplication is making an exact copy of an existing ojbect (you duplicate the key of your house). Replication is making many object from the same model, for example industry mass produtions, you replicate the same car model.

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