'Sister' in the Bible

Three sons of Zeruiah [the half sister of David] were there: Joab, Abishai, and Asahel. Now Asahel was as light and swift-footed as one of the [wild] gazelles in the field.

It happened afterwards that Absalom the son of David had a beautiful sister whose name was Tamar, and Amnon [her half brother] the son of David was in love with her.

Amnon was so frustrated because of his [half-] sister Tamar that he made himself sick, for she was a virgin, and Amnon thought it impossible for him to do anything to her.

He said to Amnon, “Why are you, the king’s son, so depressed morning after morning? Will you not tell me?” And Amnon said to him, “I am in love with Tamar, my [half-] brother Absalom’s sister.”

Jonadab said to him, “Go to bed and pretend you are sick; and when your father [David] comes to see you, say to him, ‘Just let my sister Tamar come and serve me food, and let her prepare it in my sight, so that I may see it and eat it from her hand.’”

So Amnon lay down and pretended to be sick; and when the king came to see him, Amnon said to the king, “Please let my sister Tamar come and make me a couple of cakes in my sight, so that I may eat from her hand.”

When she brought them to him to eat, he took hold of her and said, “Come, lie with me, my sister.”

So her brother Absalom said to her, “Has your brother Amnon been with you? But now keep silent, my sister; he is your brother; do not take this matter to heart.” So Tamar remained secluded in her brother Absalom’s house.

But Absalom did not speak to Amnon either good or bad; for Absalom hated Amnon because he had violated his sister Tamar.

But Jonadab the son of Shimeah, David’s brother, responded, “Do not let my lord assume that all the king’s sons have been put to death; for only Amnon is dead. This act of revenge has been on Absalom’s mind since the day Amnon violated his sister Tamar.

Absalom put Amasa in command of the army instead of Joab. Now Amasa was the son of a man named Ithra the Israelite, who had married Abigail the daughter of Nahash, [the half sister of David and] the sister of Zeruiah, Joab’s mother.