'Brother' in the Bible

and Ahijah the son of Ichabod’s brother Ahitub the son of Phinehas, the son of Eli, the Lord’s priest at Shiloh, was wearing the ephod. And the people did not know that Jonathan had gone.

Now Eliab his oldest brother heard what he said to the men; and Eliab’s anger burned against David and he said, “Why have you come down here? With whom did you leave those few sheep in the wilderness? I know your presumption (overconfidence) and the evil of your heart; for you have come down in order to see the battle.”

He said, ‘Please let me go because our family is holding a sacrifice in the city, and my brother has commanded me to attend. Now, if I have found favor in your eyes, please let me slip away so that I may see my brothers.’ That is why he has not come to the king’s table.”

Then David said to Ahimelech the Hittite and to Abishai the son of Zeruiah, brother of Joab, “Who will go down with me to Saul in the camp?” And Abishai said, “I will go down with you.”