[mgaunard]

Looked at first one (arity), saw "argument" when what was actually meant was "parameter", and therefore dismissed the document.

If you want to make a glossary, at least try to be precise.

[mtreis86]

They said 'a function takes arguments', which is correct. The arguments are passed into the function, aligning to and being bound to the function's parameters. So arity applies both to arguments the function can take, and the parameters the function has.

[mgaunard]

The way it's phrased and the examples makes it clear whoever wrote this didn't understand the distinction.