Historicity is defined by the understanding "that all meaning in discourse is historical, pointing to the social meanings that go beyond those that are linguistically articulated." (Blommaert, 2018, p. 303, as cited in Flowerdew & Richardson, 2018)
This critical approach to discourse, according to Blommaert, entails "examining the multilayered historicity running throughout people’s discourses" (p.426)
Reference
Flowerdew, J., & Richardson, J. E. (Eds.). (2018). The Routledge handbook of critical discourse studies. Routledge.