English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Where does the adjective form extensible come from and does it connote anything different than extendible? What's the difference, if any, between the two?

share|improve this question
...additionally, is there a difference between extendible and extendable? – SF. Nov 7 '12 at 8:09
-1 for not showing any research. – Matt E. Эллен Nov 7 '12 at 8:35
Historical comparison: books.google.com/ngrams/… – Peter Nore Jul 7 at 8:29

It appears that I probably draw a finer distinction here than others may, but the good thing is that for those that say the two are interchangeable, my usage will seem unremarkable, and for those that care, my usage will seem consistent.

I use extendable in cases where it means the opposite of retractable. In other words, a telescoping wand is extendable, the legs of my camera tripod are extendable.

I use extensible when I mean that the functionality of something may be increased or enhanced by the addition of an extension- an add-on module or component. My web browser is extensible because I can add an Adobe Flash extension which allows me to view flash content. I think it would sound a bit odd to talk about my web-browser being extendable.

share|improve this answer
So, if you can buy special attachments for your tripod that will allow you to mount different equipment upon it, then I suppose you'd have an extensible, extendable tripod. – J.R. Nov 7 '12 at 8:43
You may be right. I like your nuance. – tchrist Nov 7 '12 at 13:41
In this usage, extendable seems to have a perspective from the outside in, whereas extensible seems to be from inside out. – chrisdillon Feb 27 at 15:08

There are lots and lots of these. They usually came to us that way straight from Latin, and seldom mean anything different from each other. One may be more rare than another, though.

  • comprehendible, comprehensible
  • corrodable, corrodible, corrosible
  • defendable, defensible
  • deridable, derisible
  • dividable, divisible
  • evadable, evasible
  • expandable, expansible
  • explodable, explosible
  • extendible, extensible
  • inevadible, inevasible
  • invadable, invasible
  • offendable, offensible
  • persuadable, persuasible
  • protrudable, protrusible
  • reprehendable, reprehensible
  • rescindable, rescindible
  • revisable, revisible
  • subdividable, subdivisible
  • suspendible, suspensible
  • undefendable, undefensible
  • undividable, undivisible
share|improve this answer

In WordReference site, its given that extensible means capable of being extended.

extend/ɪkˈstend/ verb

1 make larger or longer in space or time.
• occupy a specified area or continue for a specified distance.

2 hold (something) out towards someone.
• offer or make available.

3 (extend to) be applicable to.

4 strain or exert to the utmost.

– derivatives
extendability noun,
extendable adjective,
extendibility noun,
extendible adjective,
extensibility noun,
extensible adjective.

Also want to add some info got from another useful source,

Extensible seems to me to indicate stretchability whereas extendable suggests an opening out or lengthening. An elastic band is extensible, i.e.: it can be stretched, whereas my lunch hour is extendable, i.e.: it can be added to, but an hour is an hour and cannot be stretched. There is also extensile which seems to mean the same as extensible.

share|improve this answer
It would be good if you could cite the source from which you quote. – Jim Nov 7 '12 at 7:15

The Oxford Dictionary for Writers & Editors says:

extendible, not -able, but in general use extensible not -able

share|improve this answer

I use the terms as Jim does in the context of Computer Science. In a computer program, if I add subroutines or blocks it is extendable - I can add more blocks. If the program is extensible, the individual blocks may be made more complex by modification, usually adding flexibility.

share|improve this answer
"made more complex by modification, usually adding flexibility". You might make them more complex, or you might simplify them. A technique used is to add flexibility, but flexibility can be a characteristic of extensible code. In short - I think your answer can be improved – Crowie Mar 5 '14 at 11:15

The Oxford Dictionary of American Usage and Style (2000) says:

Other variant adjectives, though, are merely duplicative. Typical examples are extendable, extendible, and extensible. The first of these is now prevalent in AmE (though labeled obsolete in the OED). Extensible was, through the mid-20th century, the most common form, but today it trails extendable by a substantial margin, while extendible continues to appear infrequently. Writers and editors ought to settle on the most firmly established form--extendable, which is as well formed as the variants--and trouble their minds with weightier matters.


share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.