regressus
Regressus is a Latin term that functions as both a noun meaning "a return" or "the act of returning" and as the perfect passive participle of regredi, "to go back." In classical Latin usage, it can denote either the act of returning from travel or a figurative retrogression, such as a return to an earlier state or condition. The word shows up in literary and historical texts as part of descriptions of movement, retreat, or reversal.
Grammatically, regressus is a fourth-declension noun in the masculine form, with the feminine and neuter forms
In modern scholarship, regressus is encountered primarily in discussions of Latin language, etymology, or the analysis