'Half brother' in the Bible

Then Jotham ran away to Beer and lived there to escape from Abimelech his half-brother.

He did this so the violent deaths of Jerub-Baal's seventy sons might be avenged and Abimelech, their half-brother who murdered them, might have to pay for their spilled blood, along with the leaders of Shechem who helped him murder them.

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.

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.”

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.

[Upon entering the house] he held up his hand to quiet them, then went on to explain how the Lord had rescued him from jail. He said to them, "[Go] tell all this to James [the Lord's half-brother] and to [the rest of] the brothers." Then he left [them] and went elsewhere.

Then, after they finished speaking, James [the Lord's half-brother, See 12:17] spoke up and said, "Brothers, listen to me.

The next day Paul went with us to visit James [the Lord's half-brother and a leader in the Jerusalem church], with all of the elders [of the Jerusalem church] being present.

Then He appeared to James [Note: This was probably Jesus' half-brother. See Acts 12:17; Gal. 1:19], and then to all of the apostles. [See John 20:26].