It wasn't just you, it was also AstroWolfboy who used the "generic" term in reference to the S symbol. So I just wanted to make the point that generic trademark is a thing in law.
To quote Wikipedia:
This is a real problem for Superman and DC has to always be on guard that the elements of Superman don't become so common in use that they can no longer be defended as trademark. At that point Superman becomes useless to DC and might as well be in the public domain. Some fans might prefer that--since it would put their fan fiction on the same level as all the Superman stories DC has published--but it would mean that DC would have no interest in publishing any more Superman comics, because they couldn't make money off them.A generic trademark, also known as a genericized trademark or proprietary eponym, is a trademark or brand name that has become the generic name for, or synonymous with, a general class of product or service, usually against the intentions of the trademark's holder.
A trademark is said to become genericized when it began as a distinctive product identifier but has changed in meaning to become generic. A trademark typically becomes "genericized" when the products or services with which it is associated have acquired substantial market dominance or mind share such that the primary meaning of the genericized trademark becomes the product or service itself rather than an indication of source for the product or service. A trademark thus popularized has its legal protection at risk in some countries such as the United States and United Kingdom, as its intellectual property rights in the trademark may be lost and competitors enabled to use the genericized trademark to describe their similar products, unless the owner of an affected trademark works sufficiently to correct and prevent such broad use.