user85829: What does the .ino file extension mean?
We have .cpp meaning C++, .py meaning Python, .exe meaning executable and so-on.They're obvious. The .pde file type that sketches previously used, I think, comes from processing development environment (the arduino IDE being based* on / inspired by processing).  But what does .ino mean?
There's plenty that explains what such files are, but nothing explains what those three letters mean, if anything.
* source wikipedia

user4143: 
Arduino

That's all there is to say about that really.

As commented in the source code

The file extension for sketches has changed from .pde to .ino, to avoid
conflicts with the Processing software ("ino" are the last three letters
in "Arduino").


user68310: "Arduino" is an Italian word, and "ino" is the suffix which lends itself well to a filename extension.
From Google Translate of Italian ino:

ino

Suffisso alterativo di aggettivi e sostantivi; nei primi ha valore diminutivo-vezzeggiativo, talvolta con sfumatura ironica ( biondino, carino ), oppure significa appartenenza etnica ( alessandrino, cadorino ), collegamento con materie ( argentino, salino ); nei secondi, oltre ad avere valore diminutivo-vezzeggiativo ( gattino, pensierino ), indica pure un mestiere ( ciabattino, tamburino ), uno strumento o arnese o apparecchio ( cerino, lavandino ); in alcuni casi è applicato a verbi ( imbianchino, accendino ).
In chimica organica, suffisso che nella nomenclatura ufficiale indica gli idrocarburi acetilenici, cioè gli alchini ( etino ).




Alterative suffix of adjectives and nouns; in the former it has a diminutive-pet name, sometimes with an ironic tinge (blond, cute), or it means ethnic affiliation (Alexandrian, Cadore), connection with materials (Argentine, saline); in the latter, in addition to having a diminutive-pet name (kitten, little thought), it also indicates a trade (cobbler, drummer), an instrument or tool or apparatus (match, sink); in some cases it is applied to verbs (painter, lighter).
In organic chemistry, suffix that in the official nomenclature indicates acetylenic hydrocarbons, i.e. alkynes (ethin).



85829: <p><strong>What does the <code>.ino</code> file extension mean?</strong></p>
<p>We have <code>.cpp</code> meaning C++, <code>.py</code> meaning Python, <code>.exe</code> meaning executable and so-on.They're obvious. The <code>.pde</code> file type that sketches previously used, I think, comes from <em>processing development environment</em> (the arduino IDE being based* on / inspired by <a href="https://processing.org" rel="nofollow noreferrer">processing</a>).  But what does <code>.ino</code> mean?</p>
<p>There's plenty that explains what such files are, but nothing explains what those three letters mean, if anything.</p>
<p><sub>* source <a href="https://en.wikipedia.org/wiki/Arduino" rel="nofollow noreferrer">wikipedia</a></sub></p>
 4143: <blockquote>
<p>Ardu<em><strong>ino</strong></em></p>
</blockquote>
<p>That's all there is to say about that really.</p>
<hr />
<p>As <a href="https://github.com/arduino/Arduino/blob/1.0/build/shared/revisions.txt#L5-L7" rel="nofollow noreferrer">commented in the source code</a></p>
<blockquote>
<p>The file extension for sketches has changed from .pde to .ino, to avoid
conflicts with the Processing software (&quot;ino&quot; are the last three letters
in &quot;Arduino&quot;).</p>
</blockquote>
 68310: <p>&quot;Arduino&quot; is an Italian word, and &quot;ino&quot; is the suffix which lends itself well to a filename extension.</p>
<p>From <a href="https://translate.google.com/?sl=it&amp;tl=en&amp;text=ino%0A%0A1%0ASuffisso%20alterativo%20di%20aggettivi%20e%20sostantivi%3B%20nei%20primi%20ha%20valore%20diminutivo-vezzeggiativo%2C%20talvolta%20con%20sfumatura%20ironica%20(%20biondino%2C%20carino%20)%2C%20oppure%20significa%20appartenenza%20etnica%20(%20alessandrino%2C%20cadorino%20)%2C%20collegamento%20con%20materie%20(%20argentino%2C%20salino%20)%3B%20nei%20secondi%2C%20oltre%20ad%20avere%20valore%20diminutivo-vezzeggiativo%20(%20gattino%2C%20pensierino%20)%2C%20indica%20pure%20un%20mestiere%20(%20ciabattino%2C%20tamburino%20)%2C%20uno%20strumento%20o%20arnese%20o%20apparecchio%20(%20cerino%2C%20lavandino%20)%3B%20in%20alcuni%20casi%20%C3%A8%20applicato%20a%20verbi%20(%20imbianchino%2C%20accendino%20).%0A2%0AIn%20chimica%20organica%2C%20suffisso%20che%20nella%20nomenclatura%20ufficiale%20indica%20gli%20idrocarburi%20acetilenici%2C%20cio%C3%A8%20gli%20alchini%20(%20etino%20).&amp;op=translate" rel="nofollow noreferrer">Google Translate of Italian ino</a>:</p>
<blockquote>
<p>ino</p>
<ol>
<li>Suffisso alterativo di aggettivi e sostantivi; nei primi ha valore diminutivo-vezzeggiativo, talvolta con sfumatura ironica ( biondino, carino ), oppure significa appartenenza etnica ( alessandrino, cadorino ), collegamento con materie ( argentino, salino ); nei secondi, oltre ad avere valore diminutivo-vezzeggiativo ( gattino, pensierino ), indica pure un mestiere ( ciabattino, tamburino ), uno strumento o arnese o apparecchio ( cerino, lavandino ); in alcuni casi è applicato a verbi ( imbianchino, accendino ).</li>
<li>In chimica organica, suffisso che nella nomenclatura ufficiale indica gli idrocarburi acetilenici, cioè gli alchini ( etino ).</li>
</ol>
</blockquote>
<blockquote>
<ol>
<li>Alterative suffix of adjectives and nouns; in the former it has a diminutive-pet name, sometimes with an ironic tinge (blond, cute), or it means ethnic affiliation (Alexandrian, Cadore), connection with materials (Argentine, saline); in the latter, in addition to having a diminutive-pet name (kitten, little thought), it also indicates a trade (cobbler, drummer), an instrument or tool or apparatus (match, sink); in some cases it is applied to verbs (painter, lighter).</li>
<li>In organic chemistry, suffix that in the official nomenclature indicates acetylenic hydrocarbons, i.e. alkynes (ethin).</li>
</ol>
</blockquote>
