'Half 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.

Amnon became so emotionally distressed that he fell sick over his half-sister Tamar. She was a virgin, and Amnon found it difficult to do anything to her.

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.

He had conferred with Joab the son of Zeruiah [David’s half sister] and with Abiathar the priest; and they followed Adonijah and helped him.

Now David said, “Whoever strikes down a Jebusite first shall be chief and commander.” Joab the son of Zeruiah [David’s half sister] went up first, and so he was made chief.

Zelek the Ammonite, Naharai the Berothite, the armor bearer of Joab the son of Zeruiah [David’s half sister],