'Third' in the Bible

On the third day, behold, a man came out of the camp from Saul, with his clothes torn and dust on his head. And it came about when he came to David that he fell to the ground and prostrated himself.

and his second, Chileab, by Abigail the widow of Nabal the Carmelite; and the third, Absalom the son of Maacah, the daughter of Talmai, king of Geshur;

David sent the people out, one third under the command of Joab, one third under the command of Abishai the son of Zeruiah, Joab’s brother, and one third under the command of Ittai the Gittite. And the king said to the people, “I myself will surely go out with you also.”