When I fenestrate something I put a window into it. But when I defenestrate I throw someone out of a window. Why does defenestrate not mean "remove a window"?

As examples - when someone has a detox they remove toxins. When someone de-clutters they remove clutter.

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    I think it is a 'made up word' in the sense that it is used almost exclusively in the context of the 'Defenestration of Prague' which did not involve throwing Prague out of a window. Fenestre/Fenester is the older word meaning window. It may have picked up a slightly different meaning more recently, in the sense of a quick dismissal.
    – Frank
    Aug 3, 2014 at 10:54
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    As Andrew points out, 'to take a window out of' would be disfenestrate, though there are philosophical problems there (what would be left after you did?) Aug 3, 2014 at 11:01
  • @TimLymington Probably a matter for Gilles Delueze to ponder but I imagine he might have said something like A concept is a brick. It can be used to defenestrate a building. Or it can be thrown through the window. Or you can do it yourself.
    – Frank
    Aug 3, 2014 at 11:24
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    And if someone depends (on something) do they remove pends? Or remove fer if they defer? This is a spurious interpretation of how language works.
    – Robusto
    Aug 3, 2014 at 12:11
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    The incidents (there were two) that @Frank mentioned are called "defenestrace" in Czech, which might have influenced the slightly unusual formation in English.
    – Max
    Aug 3, 2014 at 19:14

4 Answers 4


ODO gives its etymology (at defenestration) as

early 17th century: from modern Latin defenestratio(n-), from de- 'down from' + Latin fenestra 'window'.

That is, de- does not mean "remove" in this case; it retains its Latin meaning.

De- has a variety of meanings, but the sense of "removal" or "negation" comes ultimately from dis-.

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    OED has defenstrate as a 'usually jocular' back-formation (from 1917) of defenestration/defenestrated both from 1620.
    – Frank
    Aug 3, 2014 at 11:15
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    After defenestration, one's back-formation would be unlikely to result in panelessness. Aug 3, 2014 at 15:37
  • Thank you for this answer. My question shows that I need to learn a lot more about suffixes and prefixes, and that I need to get some good quality reference books (I could start with a cheap dictionary) to help.
    – DanBeale
    Aug 6, 2014 at 15:17

As Andrew points out, De- has a variety of meanings.

'Defenstrate' isn't the only word using this form. 'Deport' is essentially 'thrown out the door', and 'deplane' means to exit an airplane.

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    And decamp can mean to exit/leave the camp. Aug 3, 2014 at 19:17
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    +1 One would hope there isn't a word defenestraplane!
    – Frank
    Aug 3, 2014 at 19:18
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    @Frank there most certainly is, now :-)
    – TylerH
    Aug 4, 2014 at 14:29
  • Your mention of "deplane" reminds me of an English comedian who talks about the sometimes odd language used on English trains. I rarely hear the word "vestibule" and it's nice to hear wider vocabulary. They do use words like "detrain" and some people don't like that.
    – DanBeale
    Aug 6, 2014 at 15:20

Technically to defenestrate means to remove a window, or better, to break a pane of glass, but no English speaking person ever uses it in this manner. Fenestration is certainly an architectural term referring to windows, usually in buildings of historical interest, i.e. 'the fenestration is essentially gothic'. The only sense in which the term is commonly used in English is a colloquial one, meaning to take a woman's virginity, and likens breaking a pane of glass to breaking a hymen. 'To defenestrate' has never meant 'to throw someone out of a window'.

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    Could you add a source for using defenestration in the meaning of defloration? Aug 12, 2014 at 21:58
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    You claim that defenestrate has never meant "throw someone out of a window". A web search returns very many definitions telling me that it does mean to throw someone out of a window.
    – DanBeale
    Aug 13, 2014 at 17:34
  • The fenestra is the hole in the wall; the habit of filling in that hole with a framed slab of alabaster, glass, or an awkward sort of sieve meant to separate the breeze from the bugs is, in the grand scheme of things, a curious and relatively recent (and by no means universal) phenomenon. If defenestration meant something like unwindowing, it would have to mean bricking up the hole (or the figurative equivalent).
    – bye
    Dec 7, 2014 at 7:39
  • @bye Actually fenestra specifically relates to the glazed (glass) aperture to let light in and goes back to the Romans, whereas window originally meant an unglazed hole that let wind and light in (wind-eye etymology). Feb 11, 2018 at 0:47

Defenestrate or the "de-window" could properly refer to the act of removing a window (from a building) or, philosophically, the removal (from view) of an issue or article of argument. Taxation of glass and thus windows in the 15th century, including existing windows, by one or more of the kings of England of the period left London and most of the larger cities in the UK with bricked up windows in the walls to avoid being taxed. The bricked-up windows can be seen today in many existing buildings of the period to this day, particularly in London and Edinburgh, Scotland. "Throwing someone out of a window" is not an appropriate meaning of this term.

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    Given the top voted answer explains the situation, I don't see how this helps. Sep 23, 2016 at 16:20

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