Why is the theory of mind named as such? Theory of mind is the ability to attribute mental states—beliefs, intents, desires, emotions, knowledge, etc.—to oneself, and to others, and to understand that others have beliefs, desires, intentions, and perspectives that are different from one's own.


So am I correct in saying that for a dyadic relationship, there are 2 "theories of mind", and for a group of $n$ person, there would be $n^2-n$ "theories of mind"? I understand a system of inferences is properly called as "theory", but when so many people has different theory it loses the universal connotation as commonly used in "theory of planned behavior" or "theory of gravitation". Should it better be named as "theory-forming of other's minds"?
Probably because it was defined as:

An individual has a theory of mind if he imputes mental states to himself and others. [...]
In this paper we speculate about the possibility that the chimpanzee
may have a &quot;theory of mind,&quot; one not markedly different
from our own. In saying that an individual has a theory of mind,
we mean that the individual imputes mental states to himself and
to others (either to conspecifics or to other species as well). A
system of inferences of this kind is properly viewed as a theory,
first, because such states are not directly observable, and second,
because the system can be used to make predictions, specifically
about the behavior of other organisms.

Since this definition entails that roughly the same &quot;theory&quot; applies to all minds from a given organism's point of view, I don't see why your proposal(s) would be useful. And as far as I know neither did the thousands of papers citing that seminal work.
If you want an alternative terminology that is reasonably widely,
&quot;mental state reasoning&quot; is a good candidate... but it is somewhat narrower in that some research distinguishes between decoding and reasoning.