'Brother' in the Bible

(And Ahijah the son of Ahitub, Ichabod's brother, the son of Phinehas, the son of Eli, Jehovah's priest in Shiloh, wore the ephod.) And the people did not know that Jonathan was gone.

And Eliab, his eldest brother, heard while he spoke to the men; and Eliab's anger was kindled against David, and he said, Why art thou come down? and with whom hast thou left those few sheep in the wilderness? I know thy pride and the naughtiness of thy heart; for thou art come down that thou mightest see the battle.

and said, Let me go, I pray thee; for we have a family sacrifice in the city; and my brother himself has commanded me to be there; and now, if I have found favour in thy sight, let me go away, I pray thee, and see my brethren. He has therefore not come to the king's table.

And David spake and said to Ahimelech the Hittite, and to Abishai the son of Zeruiah, Joab's brother, saying, Who will go down with me to Saul to the camp? And Abishai said, I will go down with thee.