Question. (The title hopefully states the abstract question in full.)
Additional question: do you know more examples, possibly even clearer examples than "electron cloud" below.
- An example is
Both A=electron and B=cloud are usual nouns, and so is "electron cloud", yet an "electron cloud" is neither an electron, nor a cloud (in the water-vapour-sense).
- A non-example is "red herring": while it is true that a "red herring" in general is neither "red" nor a "herring", "red is not a noun.