'Letters' in the Bible

Now there were in Samaria seventy of Ahab's sons. And Jehu sent letters to Samaria, to the rulers of the town, and to the responsible men, and to those who had the care of the sons of Ahab, saying,

At that time, Merodach-baladan, the son of Baladan, king of Babylon, sent letters with an offering to Hezekiah, because he had news that Hezekiah had been ill.