'Âch (אָח, Strong's #251), “brother.” This word has cognates in Ugaritic and most other Semitic languages. Biblical Hebrew attests the word about 629 times and at all periods.In its basic meaning, 'âch represents a “male sibling,” a “brother.” This is its meaning in the first biblical appearance: “And she again bare his brother Abel” (Gen. 4:2). This word represents a full brother or a half-brother: “And he said to him, Go, I pray thee, see whether it be well with thy brethren …” (Gen. 37:14).

In another nuance, 'âch can represent a “blood relative.” Abram’s nephew is termed his “brother”: “And he brought back all the goods, and also brought again his brother Lot, and his goods, and the women also, and the people” (Gen. 14:16). This passage, however, might also reflect the covenantal use of the term whereby it connotes “ally” (cf. Gen. 13:8). In Gen. 9:25, 'âch clearly signifies “relative”: “Cursed be Canaan; a servant of servants shall he be unto his brethren.” Laban called his cousin Jacob an 'âch: “And Laban said unto Jacob, Because thou art my brother, shouldest thou therefore serve me for nought?” (Gen. 29:15). Just before this, Jacob described himself as an 'âch of Rachel’s father (Gen. 29:12).

Tribes may be called 'âchim “And [the tribe of] Judah said unto [the tribe of] Simeon his brother, Come up with me into my lot …” (Judg. 1:3). The word 'âch is used of a fellow tribesman: “With whomsoever thou findest thy gods, let him not live: before our brethren discern thou what is thine …” (Gen. 31:32). Elsewhere it describes a fellow countryman: “And it came to pass in those days, when Moses was grown, that he went out unto his brethren, and looked on their burdens …” (Exod. 2:11).

In several passages, the word 'âch connotes “companion” or “colleague”—that is, a brother by choice. One example is found in 2 Kings 9:2: “And when thou comest thither, look out there Jehu the son of Jehoshaphat the son of Nimshi, and go in, and make him arise up from among his brethren, and carry him to an inner chamber” (cf. Isa. 41:6; Num. 8:26). Somewhat along this line is the covenantal use of the word as a synonym for “ally”: “And Lot went out at the door unto them, and shut the door after him, and said, I pray you, brethren, do not so wickedly” (Gen. 19:6-7). Notice this same use in Num. 20:14 and 1 Kings 9:13.

'Âch can be a term of polite address, as it appears to be in Gen. 29:4: “And Jacob said unto them [shepherds, whose identity he did not know], My brethren, whence be ye?”

The word 'âch sometimes represents someone or something that simply exists alongside a given person or thing: “And surely your blood of your lives will I require; at the hand of every beast will I require it, and at the hand of … every man’s brother will I require the life of man” (Gen. 9:5-6).

Bibliography Information
Vines, W. E., M. A. Entry for 'Brother'. Vine's Expository Dictionary of OT Words. https://www.studylight.org/dictionaries/eng/vot/b/brother.html. 1940.

Bible Dictionaries Brother

Vine's Expository Dictionary of OT Words

Bible Dictionaries
Brother