Substrings used in a trademark
<p><code>The Linux Foundation</code> is a registered trademark of The Linux Foundation.</p>

<p><code>Linux</code> is a registered trademark of Linus Torvalds.</p>

<p>But <code>Linux</code> is a substring of <code>The Linux Foundation</code>.</p>

<p>Is it OK for someone to claim a trademark including another trademark as a substring (such as <code>The Linux</code>, <code>My Linux</code>, <code>Free Linux</code>, etc.)?</p>

<p>The trivial answer is yes, at least under certain circumstances, as the example you give shows.</p>

<p>First, the concept of substrings is not particularly useful in trademark law.  IF that were the case, then we wouldn't be able to have a company called "<a href="http://tess2.uspto.gov/bin/showfield?f=doc&amp;state=4806:i6tmj0.8.1" rel="noreferrer">Gaudiest Clothing Brand</a>" because it contains the substring <em>audi.</em></p>

<p>But, you might say, what about looking at <em>words</em> instead of <em>characters,</em> as with the example of "Linux" and "The Linux Foundation."  In that case, I offer the example of "Target," which is a word found in <a href="http://tess2.uspto.gov/bin/showfield?f=toc&amp;state=4806%3Ai6tmj0.1.1&amp;p_search=searchss&amp;p_L=50&amp;BackReference=&amp;p_plural=yes&amp;p_s_PARA1=&amp;p_tagrepl%7E%3A=PARA1%24LD&amp;expr=PARA1+AND+PARA2&amp;p_s_PARA2=target&amp;p_tagrepl%7E%3A=PARA2%24COMB&amp;p_op_ALL=ADJ&amp;a_default=search&amp;a_search=Submit+Query&amp;a_search=Submit+Query" rel="noreferrer">literally thousands of US trademarks</a>.</p>

<p>You'll notice that the first item on this list where word mark is simply <em>target,</em> rather than a phrase containing that word, doesn't even belong to the <a href="http://www.target.com" rel="noreferrer">well known chain of stores</a>.  This brings us to another <a href="https://en.wikipedia.org/wiki/Trademark#Fundamental_concepts" rel="noreferrer">important aspect of trademark protection</a>, which is that the mark's purpose is to identify a producer of goods, a provider of services, or particular goods or services themselves.  You could probably start a bookstore called McDonald's, <a href="http://www.mcdonaldsbookexchange.com" rel="noreferrer">unless you're near Redmond, Washington</a>, but you certainly would not be able to use that name for <a href="http://www.mcdonalds.com" rel="noreferrer">a chain of hamburger-based fast food restaurants</a>.</p>

<p>Back to the subject of Linux, one possible explanation here is therefore that <em>Linux</em> is a trademark for an operating system, while <em>The Linux Foundation</em> is a trademark for a non-profit foundation that is concerned with the operating system.  The trademarks don't represent competing entities.  Consider, for example, the disclaimer on <a href="http://volkswagenownersclub.com/vw/" rel="noreferrer">volkswagenownersclub.com</a>:</p>

<blockquote>
  <p>VolkswagenOwnersClub.com is an independent media publication. VolkswagenOwnersClub.com and its owners are not affiliated with or endorsed by Volkswagen AG or Volkswagen of America, Inc. Volkswagen is a registered trademark of Volkswagen AG. All rights reserved. All information Copyright 2006-2010 </p>
</blockquote>

<p>(Also consider, for example, the case of <a href="https://en.wikipedia.org/wiki/Apple_Corps_v_Apple_Computer" rel="noreferrer">Apple Corps, Ltd. and Apple Computer, Inc.</a>.)</p>

<p>As far as I can tell, however, "Volkswagen Owners' Club" is not directly relevant to this question, because it is not a registered trademark, and the question concerns two registered trademarks.  I am not sure whether two such trademarks could coexist if there were an adversarial relationship between their owners.</p>

<p>In this case, hwoever, the trademarks are used together because the owners have a collegial relationship.  They work for a common goal, the promotion of the product identified by one of the trademarks.  The foundation's use of the trademark is therefore undoubtedly with permission.  In fact, the Linux foundation is <a href="https://en.wikipedia.org/wiki/Linus_Torvalds" rel="noreferrer">Linus Torvalds' employer</a>, and <a href="https://en.wikipedia.org/wiki/Linux_Foundation#Goals" rel="noreferrer">one of the foundation's purposes</a> is <a href="http://www.linuxfoundation.org/about/linux-foundation-trademark-usage-guidelines" rel="noreferrer">to manage the Linux trademark</a> that Torvalds owns.</p>

<p>Now the question of derivative trademarks, such as <em>My Linux</em> is clouded by the fact that Linux is an open source operating system.  In principle, you can't modify a product and then sell it using its original trademark unless you have permission.  For example, I don't suppose I could rebottle <a href="https://www.coca-colacompany.com/" rel="noreferrer">Coca-Cola</a> with some added salt and pepper and sell it as *Phoog's Coca-Cola" unless I had permission from the owner of the trademark.</p>

<p>With Linux being an open-source project, however, the terms of the open source license probably explicitly permit people to use the trademark under certain restrictions if they offer, for example, a customized distribution of Linux</p>

trademark