Am I the only person who sometimes makes an exception for "two" ?
In all such cases it makes sense that a language/ construct/library special-cases 2 elements without generalizing for an arbitrary number of elements.
By the way, 3 is much less common, except in some specific domains, like 3D vectors, UNIX permissions (user, group, other), etc.
Yes, you are correct! Ancient Greek has a dual number, which is used specifically for referring to two people or two objects. The dual is a distinct grammatical number, separate from singular and plural.
In the ancient Greek language, nouns, pronouns, adjectives, and verbs all have different forms for singular, dual, and plural numbers. The dual number is used when referring to two things or two people, while the singular number is used for one thing or one person, and the plural number is used for three or more things or people.
The dual number is no longer used in modern Greek, but it was an important feature of the ancient Greek language, which had a rich and complex system of inflectional morphology. Other languages that have a dual number include Old English, Old Norse, Lithuanian, and Slovenian, among others.
But I have the decency to feel bad and leave an apologetic comment.
See also this example in Wikipedia of a ternary relation: https://en.wikipedia.org/wiki/Finitary_relation#Example
Another example: If you have a table (SSN, Name, DateOfBirth), then that corresponds to the relation "person with SSN x has name y and date of birth z". In that case it's a relation between SSNs, names, and dates.