Coliteracy is meant as an analogy with [covariance].
The coliteracy of two parties is, loosely, the degree to which they have a shared language with stable meanings, subject to a domain of discussion. Here, the "meaning" of a word or contextual utterance is unspecified, but intuitively refers to a probability space of other utterances and inarticulated experiences that the subject would rate as synonymous. The coliteracy of two parties against a single contextual utterance, then, can be imagined as the "overlap" in their respective distributions, summed over all utterances (weighted by the likelihood of the utterance in the discursive domain).
Discussions with low coliteracy can be found in Flat Earth-related groups on Facebook. Notably, scientific and mathematical literacy is required to stabilize the meanings of many of the terms involved.
Academic departments seek to structure themselves and their relationships with other universities, in order to certify that "graduates" should expect high coliteracy with similarly credentialed parties.
Social media tools such as tagging and search have enabled members of progressively niche subcultures to gravitate toward stable meanings and continuously negotiate their shared language.
Intersectional and so-called "culture war" discussions are thought to span the range of coliteracy.