What is a word/phrase for using a term for a popular special case instead of a generic term?

Some people use a term for a popular special case in place of a generic term. (Often this popular special case is a particular product in that category.) I think that this is a common phenomenon. Is there any word/phrase for it?

For example, “Coke” officially refers to a Coca-Cola (I think), but some people seem to call any carbonated soft drinks “Coke.” In Japanese, famikon is the Japanese name for Nintendo Entertainment System (NES), a video game console which was extremely popular in 1980s and early 1990s, but some Japanese people call any video game console famikon even if it is not really a famikon. (As an aside, calling a video game console famikon when it is not really a famikon is even a stereotype of a “mother unfamiliar with technology” in Japan.) I am looking for a term which refers to this kind of usage of words.

Solution 1:

I believe the correct term is proprietary eponym or genericized trademark depending on whether the company retains the trademark or not, respectively.

Solution 2:

I agree with proprietary eponym and genericized trademark and have given +1 to the other answers. These both fall under the more general term synecdoche.

Solution 3:

Perhaps I'm misunderstanding, but I believe they're called genericized trademarks.

It basically means people are using trademarked names as a descriptor for products that are similar to the original branded product. A very prominent example of this is Google/Googling. Other examples include Kleenex, Aspirin and Sharpie.

I'm not entirely sure if the "coke" example exactly fits in since the generic term is different from the brand. The Japanese game consoles are a good example of genericized trademarks though.

Further reading

Solution 4:

It is called a genericized trademark or proprietary eponym.