When brand names become generic trademarks
All these names are examples of the best and at the same time the worst thing that can happen to a brand: They are generic brand names, i.e. products that have become so successful that they now (have to) stand as the name or generic term for an entire genre.
Wikipedia says: "A generic trademark, also known as a genericized trademark or proprietary eponym, is a trademark or brand name that, because of its popularity or significance, has become the generic term for, or synonymous with, a general class of products or services, usually against the intentions of the trademark's owner." (Source)
In linguistics, terms that have made the transition from a proper name to a generic name are called deonyms - composed of the Greek words for "god" and "name". The field of deonyms is not limited to brand names, by the way: The verb "to x-ray", for example, in German is "Röntgen" and is derived from the discoverer of the rays named after him and is also a deonym.
Generic brand names are everywhere!
But let's go back to brand names that, due to their market penetration, suddenly become more than just a name for a product: a 
Instead of handkerchief, people in Germany say "Tempo", even if it is a product of a different brand. We call transparent adhesive tape for the desk "Tesa". "Labello" is used synonymously with lip balm. And even with the (somewhat outdated) "Walkman" and "Discman", with "Vaseline" and "Autan", with "Tupperware" and "Vespa", deonymisation does not stop. Did you know that even "Dynamite" and "Bobby-Car" are actually brand names?
Sometimes generic trademarks change word class and become verbs: "Flexen", "Kärchern", "Fönen" and even "Einwecken" are all German verbs originally derived from brand names. Not forgetting, of course, the brand that provides the verb for all search engine queries around the world: "to google".
What's wrong with generic trademarks?
But it's great when a brand is so successful that its name is used synonymously with a whole class of products, you would think. Sounds like it at first, because after all, it speaks for the success of the brand when such a high market penetration and attention is generated by the name. Or does it? In fact, two problems arise:
- The brand becomes diluted. If every dictionary is only referred to as "Duden", the brand essence is lost. In the worst case, consumers no longer know the brand. They call every dictionary that, regardless of the manufacturer and quality. At the same time, a very important aspect for a strong brand is lost: it should be clearly identifiable and assignable.
- Renewal of trademark protection can be refused. This happened to Deutsche Post AG in 2008, for example. The German Federal Patent Court ruled that the registered trademark "Post" had to be canceled on the grounds that "the word Post serves in common parlance (...) to designate a service institution which receives, transports and delivers letters, parcels, monetary items and other objects...". (source) and was thus not eligible for protection. Although the judgment was overturned by the Federal Supreme Court a short time later, it clearly shows the problems inherent in such generic terms. Even if one is proven right, disputes in court cost money and time.
In conclusion, if your trademark faces the "danger" of becoming a generic name, then you have first of all done everything right. But then find a good lawyer who will make sure it stays that way! ;)
But don't worry, dear founders, entrepreneurs and marketing managers out there: the risk of your brand becoming generic is really not very high. Especially if you are at the very beginning with your product or company. Therefore, you can first of all relax and start searching for a name. A cool brand name generator makes it easy for you.
What examples of brand names can you think of that have what it takes to become generic trademarks?
