An action perimeter is different from a function because, for instance, you can write (if <test> <then-clause> <else-clause>).
For a function, all its arguments are evaluated first and then it is applied. That's certainly not the case for if since the whole point of a condition is to refrain from evaluating some code unless a condition is met.
Hence, in Lisp, the simple notation encompasses and is fully operative on every action, including the ones that do not behave like functions. While in many language chaining perimeters is only about function calls. And in addition it is rarely idiomatic to chain function calls in such language.
Thank you for pointing out the similarity between parameter and perimeter which borders on confusion. Thanks to everyone who brought it up to!
It's clear that's an issue I overlooked. The reason is I use the term argument in English and in French, never parameter itself. But that's probably because once I realized the notion of a perimeter is important in Lisp, I stopped using the word 'parameter'.
Sorry for that! I'll try to find a better term.