{Function, structure, process, behaviour} Differences and definitions?

In a brief chat with @daviding recently, I asked him to recall for me the phrasing of a question I’ve heard him ask a few times:

“Which comes first, process or structure?”

He also added:

“This is in most of my lectures when I’m discussing the basic Ackoff definitions of function, structure, process (and now I’ve added behaviour)”

David’s response lead me to create this topic, to explore follow-up questions more openly. How are the concepts in this set of 4 defined? How are they different from each other, how do they relate?

To see why I refer to this question as part of a university lecture, the interested might follow through to a 2020 lecture (at about 49m30s).

To get a bigger context about systems definitions, it might be helpful to back up to about 40m00s.

The blog post on this first of four lectures on " Are Systems Changes Different from System + Change?" at http://coevolving.com/blogs/index.php/archive/are-systems-changes-different-from-system-change/ .