'Sister' in the Bible

Sometime after this, David's son Amnon fell in love with David's other son Absalom's beautiful sister Tamar.

"Why are you so depressed these past few mornings," Jonadab asked Amnon, "since you're a son of the king? Why not tell me?" Amnon replied, "I'm in love with my brother Absalom's sister Tamar."

Jonadab advised him, "Lie down and pretend to be sick. When your father visits you, ask him, "Please let my sister Tamar come and give me something to eat that she prepares especially for me, and after she makes dinner for me, let her feed it to me personally.'"

So Amnon lay down and pretended to be sick. When the king came to visit him, Amnon asked the king, "Please let my sister Tamar come and make some of her bread especially for me, so she can feed it to me personally."

But as soon as she brought them near him to eat, he overpowered her and told her, "Come here and have sex with me, my sister!"

Later, her brother Absalom asked her, "Has Amnon, that brother of yours, raped you? Then keep quiet about your half-brother for now, my sister. Stop taking this so personally." From that time on, Tamar lived in continuous desolation within her brother Absalom's house.

But Absalom never said a word, either good or bad, to Amnon. Nevertheless, he hated Amnon because he had humiliated his sister Tamar.

But David's brother Shimeah's son Jonadab reported, "Your majesty, don't assume they've killed all of the young men the king's sons only Amnon has died, since that was Absalom's intention from the day Amnon raped his sister Tamar.

Absalom had installed Amasa in place of Joab over the army. (Amasa was the son of a man named Jether the Ishmaelite. His mother was Abigail, a daughter of Nahash and a sister of Zeruiah, Joab's mother.)