One of my kids calls water fountains water mountains.. I assume from just mishearing the word. The first time he said it I went to correct him and then I'm like it does look like a water mountain so fuck it we'll go with that. Now the whole family only refers to them us water mountains.

And oddly there is another misheard word another of my kids used that we've all adopted, this kid said his tshirt was skin side out instead of inside out. Again I went to correct him and thought no he is right too, so now clothes are skin side out or skin side in.