I appreciate the detailed response. I am aware of the information theoretic definition, and I get that this definition is rejected or controversial. From the wiki you cited,

> Another interpretation is given by communication theorists Claude Shannon and Warren Weaver, who characterize communication as a transmission of information brought about by the interaction of several components, such as a source, a message, an encoder, a channel, a decoder, and a receiver.[17] *The transmission view is rejected by transactional and constitutive views, which hold that communication is not just about the transmission of information but also about the creation of meaning.* (emphasis mine)

I’ll go one step further and say that I don’t think the Shannon definition of communication applies to physical responses to external stimuli (reflexive knee response, signals produced by plants when cut), or signals produced by chemical reactions (light given off the stars or suns).

Induced reactions or chemical changes are not communication per se because the meaning of the transmitted signal would not exist without an observer as there’s no internal mechanism which creates the signal without the observer.

In cell to cell communication, for example, a cell will create signals without the existence of another cell to interpret those signals. If a second cell picks up those signals, then it’s receiving communication. If however the second cell produces a stimulus to invoke a response from the first cell, the signal received would not have existed without the observer. In this sense, I think communication depends on the ability to transmit information without the provocation of observers or receivers, which is especially meaningful for biological systems because the signals they convey determine their survival.

By simply existing does not mean something is communicating (sun or stars), and reacting to external stimuli does not represent communication per se, only signaling.