Etymology of the Latin word epistola
the Latin word epistola (letter, dispatch, written communication)
derived from the Greek word epistole, ἐπιστολή (a written message)
derived from the Greek word stellein, στέλλω (to send)
derived from the Proto-Indo-European root *stel-
derived from the Greek word epistellein, ἐπιστέλλω (to enjoin (by writing); (genitive case) to communicate by letter (for any purpose))