Quote Originally Posted by factotum View Post
You seem to be complaining that people use the word "tsunami" when the English phrase "tidal wave" exists, but as you also point out, those are names for two different things? A tsunami is a large wave caused by a displacement of water, e.g. by a landslide or an earthquake, whereas a tidal wave is a storm surge or tidal bore. Calling an earthquake-derived wave a "tidal wave" is just plain wrong, regardless of it being commonly done.
I believe I noted in the very post that you quote that I learned they are (slightly) different things, and that therefore it was not the best possible example of the phenomenon to which I was referring, merely the one that first came to mind.

If you would prefer a better example, how about when people use the phrase "a certain je ne sais quoi" to describe a positive quality that they don't have the right words for? It literally just means "I don't know what," but in French, so why not just say that?