Yes, this is an issue. Couple of thoughts: (A) The second and third definitions of "key" are not different. We talk about "private key" and "public key". A key

Yes, this is an issue. Couple of thoughts: (A) The second and third definitions of "key" are not different. We talk about "private key" and "public key". A key in this sense is information provided to a transformation algorithm to tell it how to do the transformation. If we do not wish others to be able to do the transformation, then we keep the key secret. The secrecy should not be part of the definition of "key". (B) What about key as in "sorting key"? That's a bit like definition 1, but not quite. (C) An issue that feels related to me is when all synonyms for a particular concept are defined as technical terms, and we run out of words to use. Say I want to talk about what "type of thing" something is. I can't use "type"; that means something very specific. So does "sort". So does "category". So does "class". I used to use "kind", but then somebody made a technical term out of that, too.[1] What's left? "Breed"? "Ilk"? [1] https://en.wikipedia.org/wiki/Kind_%28type_theory%29 https://en.wikipedia.org/wiki/Kind_%28type_theory%29