I often see "functional" used as an adjective in situations where I think that "function" would actually be the better choice. Specifically, I am referring to translations of German compound nouns.
Here is an example: Funktionsarchitektur. This is the architecture of the function/functions. To be specific, we are talking about a technical function in a machine or vehicle. This is the architecture of the devices, control units, etc. which perform the specific function. ABS would be one example.
In this case I would use "function architecture", translating it as a compound noun in English as well. For me, "functional architecture" is an architecture which functions and not an architecture of/for functions.
I see a lot of cases in which the adjective "functional" is used instead of expanding the compound noun.
Any thoughts on this?