Null, nil and naught are all synonyms of zero, and to my knowledge, zero is the only number that has this many cognitive synonyms, if not more. Why is this?
Does it have to do with English being significantly influenced by both Germanic and Latin, leading to many synonyms with different historic roots, this number being an example of that? Or are there other factors at play? Zero is more than just a number, it is a concept, the concept of nothing, which would probably warrant many entities putting a name on it; does it have anything to do with that?