# Which is better: "Interaction of x with y" or "Interaction between x and y"

Which one is better to use:

Interaction of x with y

or

Interaction between x and y?

Or are they equally correct? In that case, is there a difference between them, or are they basically interchangeable?

My instinctive response is: "interaction of x with y" is to describe what x is doing to y, but not what y is doing to x.

"Interaction between x and y" describes what both are doing with each other.

See, one is one way, and the other is both ways.

However, the word "interaction" itself assumes that there is already a 2-way action going on.

So the combination of the symmetric concept interaction along with the one-way structure "of x with y" makes the phrase ambiguous. Which is meant, "x on y", or "both x on y and y on x"?

Hence I would always go with the second, especially if I were writing a technical document meant to explain something. Otherwise I would write "the action of x on y" if I meant just the one-way action.

• I question the ambiguity of "interaction of x with y." It is perfectly sensible to talk about the interaction of a user with a computer. There is a two-way communication (user presses buttons, computer displays responses), but the emphasis is on what the user can or cannot do. A craftsman does not act on a tool, he interacts with a tool to act on a raw material. Jan 22, 2021 at 5:28
• @MarkH wot-eva. Jan 22, 2021 at 5:57

They are different and not necessarily interchangeable. You would need to provide greater context for us to determine which would be correct.

To illustrate; interaction of x with y does not necessarily imply any agency on the part of y (although it could), simply that x is acting.

Conversely, interaction between x and y necessarily implies agency with both parties, x and y.

To get almost exactly the same meaning between both, you would have the following:

Interaction of x and y

Interaction between x and y

• In theory yes I agree, except that the word interaction already automatically implies that they are both acting upon each other. Jan 21, 2021 at 11:33
• I take your point but I would say that 'interaction' does not necessarily imply this: 'interaction of x on y', for example. 'With' is ambiguous here and it certainly could imply agency of both parties, though I would still state not necessarily. Jan 21, 2021 at 11:37
• Hmm ... I think this warrants an answer of my own. Jan 21, 2021 at 11:38
• ... in which it turns out I completely agreed with what you wrote. Jan 21, 2021 at 11:47
• No problem. I think it adds some necessary nuance with respect to the the prefix inter which does mean between, as you state. Jan 21, 2021 at 11:49