Where are the &quot;United States Classification&quot; codes for trademarks defined?
<p>I'm attempting to do some preliminary research on trademarks and having trouble with the US classification codes. E.g., I'm looking at a 'Goods and Services' description that starts with "IC 042. US 100 101."</p>

<p>The IC designation is clear enough and it's easy enough to find <a href="https://www.uspto.gov/trademark/trademark-updates-and-announcements/nice-agreement-current-edition-version-general-remarks" rel="nofollow noreferrer">IC definitions</a>.</p>

<p>However, I can't find the US class definitions. I understand the IC system is the primary classification used for trademarks, however all (?) the trademark applications I see include 'US' code numbers as well, following the IC numbers and the <a href="https://tmep.uspto.gov/RDMS/TMEP/current" rel="nofollow noreferrer">Trademark Manual of Examining Procedure</a> refers to the US codes as "secondary".</p>

<p>So, it seems the US codes are still useful—though secondary—but not defined anywhere I can find. Or should I just not worry about the US codes?</p>

<p>Trademark class codes are entirely different than patent class codes. The tile of the question uses the word trademark but the question itself says you are looking into patents. Although both are handled by the USPTO, the "T" side and the "P" side of that agency are very distinct. Trademark classification in the US uses the international <a href="https://www.wipo.int/classifications/nice/en" rel="nofollow noreferrer">Nice Classification</a> Agreement as you have linked to. </p>

<p>The traditional US patent classification system is called <a href="https://www.uspto.gov/web/patents/classification/selectnumwithtitle.htm" rel="nofollow noreferrer">USPC</a>. It is based on a class/subclass format and, since our system is very old we have Class 4</p>

<blockquote>
  <p>004   Baths, closets, sinks, and spittoons</p>
</blockquote>

<p>Where we find subclass</p>

<blockquote>
  <p>4/ 300    Flush closet: Subject matter receptacle for receiving bowel
  material and/or a liquid handling means to assist the removal of the
  bowel material from the receptacle.</p>
</blockquote>

<p>There is an international patent classification system (IPC) and a European classification system <a href="https://worldwide.espacenet.com/help?topic=ecla&amp;locale=en_EP&amp;method=handleHelpTopic" rel="nofollow noreferrer">ECLA</a></p>

<p>Both of these are newer than the USPC. Their organization might be compared to the metric vs our ad hoc measuring systems. In ECLA-</p>

<blockquote>
  <p>A HUMAN NECESSITIES PERSONAL OR DOMESTIC ARTICLES</p>
</blockquote>

<p>A47 FURNITURE;</p>

<blockquote>
  <p>DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION
  CLEANERS IN GENERAL</p>
</blockquote>

<p>A47K SANITARY EQUIPMENT NOT OTHERWISE PROVIDED</p>

<blockquote>
  <p>FOR (connecting to water supply or waste pipe, sinks E03C;
  water-closets E03D); TOILET ACCESSORIES (cosmetic equipment A45D) 
  A47K13/00 Seats or covers for all kinds of closets  (dog or cat
  toilets adapted to fit on conventional toilets A01K1/0121) </p>
</blockquote>

<p>A47K13/02       •    of plastic materials.</p>

<p>Recently the US and the EPO created yet another system the <a href="https://www.uspto.gov/web/patents/classification/cpc/html/cpc.html" rel="nofollow noreferrer">CPC</a>. The Cooperative Patent Classification system is very similar to the ECLA but with a finer gradation of subclasses. In the last two years it seems the transition to CPC at the USPTO is happening.</p>

trademark