With a lot of focus towards customisation of software functionality and interface components, there are some software platforms that choose to go down the path of creating APIs and exposing some of the internal code to allow customers to extend the features and functions of their software.

This often creates an overlap or conflict in how the terms 'extensions', 'plug-ins', 'add-ons' and 'widgets' are used because some refer to the technical implementation details or the way users go about the customisation process, but they are still essentially the same type of interface components that is presented on the screen. Here is a previous answer from StackOverflow as well for reference in the browser context (https://stackoverflow.com/questions/33462500/exact-difference-between-add-ons-plugins-and-extensions).

The use of the word 'extension' seems to come from the concept of extensibility in software architecture and design, while the word 'plug-in' seems to be an adoption of the physical object. However, both terms seem to be used interchangeably depending on the actual context, which could be for browsers, software platforms, standalone apps, etc.

While for the developer it may make sense to distinguish and keep these terms separate, the need for a consistent language to be displayed on the interface (e.g. menu) and documentation is still there. So from a user's point of view, can these terms co-exist or will it just cause confusion?

  • 2
    I think widget is very different to the other terms. Also, I don't think there's a correct answer for this question, all terms are really ambiguous and mean different things for different people or users, and even the same people but different contexts.
    – Devin
    Aug 8, 2022 at 17:28
  • @Devin I often find widget mentioned when there's dashboard interfaces or components being designed or built, and I wonder if in this context it will cause confusion.
    – Michael Lai
    Aug 8, 2022 at 23:01

2 Answers 2


Multiple words for the same thing are always an annoyance. It will not break your software but your users will question the level of quality provided by your teams. It's a red flag for your users. In the back of their mind they ask themselves why you are not consistent with words. Most teams I know have some kind of small glossary with words and descriptions they decided to use within a product's scope.


Typical Answer Incoming

It depends on your users.

Each of these terms are distinguished by the computer literate and can even be used to determine a level of computer literacy of your target demographic. Those with less computer literacy are far less likely to know (or care) what the differences are.

External Consistency: 2 Roads Diverged...

Reading over (and interpreting a bit) the SO link, it appears that experienced software engineers who develop/use/work with extensions, plug-ins, and add-ons see a distinction between these objects. Except add-ons: which seem to be more of a generic term some organizations use. In these communities, the terminology is important.

For businesses and products that utilize, plug-ins, extensions, and /or add-ons, the terms are used more loosely and inconsistently. Likely as they have a broad audience including many with average to low computer literacy. The SO link actually calls out these inconsistencies in the questions.

Internal Consistency (Assuming Average or Low Computer Literacy)

Seems this is your goal and using any of one of these terms to represent all three is probably acceptable for individuals with lower computer literacy. Knowing what the specific add-on, extensions, plug-in does is more important.

Except! I recommend being careful with the term "plug-in" for lower computer literacy users. This term has been associated with Adobe Flash and the security risks involved with that plug-in (it matches the software engineering definition). The public is likely more aware of this due to the media attention it once had with Apple's iPhone products. Lower literacy users could be wary of any plug-ins, believing all or any of them could be a security risk. Test impressions of the term "plug-in" before using it within your application.

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