Strong's #251: 'ach (pronounced awkh)
 a primitive word; a brother (used in the widest sense of literal relationship and metaphorical affinity or resemblance (like 1)):--another, brother(-ly); kindred, like, other. Compare also the proper names beginning with "Ah-" or "Ahi-".
Brown-Driver-Briggs Hebrew Lexicon:
 
  'âch 
 
 1) brother
 
 1a) brother of same parents
 1b) half-brother (same father)
 1c) relative, kinship, same tribe
 1d) each to the other (reciprocal relationship)
 1e) (figuratively) of resemblance
 
  Part of Speech: noun masculine
Relation: a primitive word
Usage:
This word is used 629 times:
2 Chronicles 28:15: "them to Jericho, the city of palm trees, to  their brethren: then they returned to Samaria."
2 Chronicles 29:15: "And they gathered  their brethren, and came, according to the commandment of the king, by the words"
2 Chronicles 29:34: "all the burnt offerings:  wherefore their brethren the Levites did help them, till the work"
2 Chronicles 30:7: "And be not ye like your fathers,  and like your brethren, which trespassed against the LORD God"
2 Chronicles 30:9: "if ye turn again unto  your brethren and your children shall find compassion before them that lead them captive,"
2 Chronicles 31:12: "the Levite was ruler, and Shimei  his brother was the next."
2 Chronicles 31:13: "under the hand of Cononiah and Shimei  his brother, at the commandment of Hezekiah the king,"
2 Chronicles 31:15: "in the cities of the priests, in their set office, to give  to their brethren by courses, as well to the great as to the small:"
2 Chronicles 35:5: "place according to the divisions of the fathers  of your brethren the people, and after the division of the families"
2 Chronicles 35:6: "the passover, and sanctify yourselves,  your brethren, that they may do according to the word of the LORD by the hand"
2 Chronicles 35:9: "Conaniah also, and Shemaiah and Nethaneel,  his brethren, and Hashabiah and Jeiel and Jozabad, chief"
2 Chronicles 35:15: "depart from their service; for  their brethren the Levites prepared"
2 Chronicles 36:4: "of Egypt made  his brother king over Judah and Jerusalem,"
2 Chronicles 36:4: "And Necho took Jehoahaz  his brother, and carried him to Egypt."
2 Chronicles 36:10: "and made Zedekiah  his brother king over Judah and Jerusalem."
Ezra 3:2: "Jeshua the son  and his brethren the priests, and Zerubbabel the son of Shealtiel,"
Ezra 3:2: "and Zerubbabel the son of Shealtiel,  and his brethren, and built the altar of the God"
Ezra 3:8: "the son of Jozadak, and the remnant  of their brethren the priests and the Levites, and all they that were come"
Ezra 3:9: "Then stood Jeshua with his sons  and his brethren, Kadmiel and his sons, the sons of Judah,"
Ezra 3:9: "of God: the sons of Henadad, with their sons  and their brethren the Levites."
Ezra 6:20: "for all the children of the captivity,  and for their brethren the priests,"
Ezra 8:17: "and I told them what they should say unto Iddo,  and to his brethren the Nethinims, at the place"
Ezra 8:18: "the son of Israel; and Sherebiah, with his sons  and his brethren, eighteen;"
Ezra 8:19: "him Jeshaiah of Merari,  his brethren and their sons, twenty;"
Ezra 8:24: "of the chief Sherebiah, Hashabiah, and ten of their brethren  of their brethren with"
Ezra 10:18: "namely, of the sons of Jeshua the son of Jozadak,  and his brethren; Maaseiah, and Eliezer,"
Nehemiah 1:2: "That Hanani, one of my brethren,  of my brethren, he and certain men of Judah;"
Nehemiah 3:1: "the high priest  with his brethren the priests, and they built the sheep"
Nehemiah 3:18: "After him repaired  their brethren, the son of Henadad, the ruler of the half"
Nehemiah 4:2: "And he spoke before  his brethren of Samaria, and said, What do"
Nehemiah 4:14: "which is great and terrible, and fight for  your brethren, your sons, and your daughters, your wives,"
Nehemiah 4:19: "the wall, one far from another.  from another."
Nehemiah 4:23: "So neither I,  nor my brethren, nor the men of the guard which followed"
Nehemiah 5:1: "and of their wives against  their brethren the Jews."
Nehemiah 5:5: "Yet now our flesh is as the flesh  of our brethren, our children as their children: and, lo, we"
Nehemiah 5:7: "exact usury, every one  of his brother. And I set a great assembly against"
Nehemiah 5:8: "after our ability  our brethren the Jews, which were sold unto the heathen; and will ye"
Nehemiah 5:8: "even sell  your brethren? or shall they be sold unto us? Then held they their peace, and found nothing"
Nehemiah 5:10: "I likewise,  and my brethren, might exact of them money and corn: I pray"
Nehemiah 5:14: "of Artaxerxes the king, that is, twelve years, I  and my brethren have not"
Nehemiah 7:2: "That I gave  my brother Hanani, the ruler of the palace, charge over"
Nehemiah 10:10: " And their brethren, Shebaniah, Hodijah, Pelaiah, Hanan,"
Nehemiah 10:29: "They cleaved to  their brethren, and entered into a curse, and into an oath, to walk"
Nehemiah 11:12: " And their brethren that did the work were eight hundred twenty and two:"
Nehemiah 11:13: " And his brethren, chief of the fathers, forty and two: and Amashai the son"
Nehemiah 11:14: " And their brethren, mighty men of valor, twenty and eight: and their overseer"
Nehemiah 11:17: "in prayer: and Bakbukiah the second among his brethren,  among his brethren, and Abda the son of Shammua,"
Nehemiah 11:19: "Moreover the porters, Akkub, Talmon,  and their brethren that kept the gates, were a hundred seventy"
Nehemiah 12:7: "These were the chief of the priests  and of their brethren in the days of Jeshua."
Nehemiah 12:8: "which was over the thanksgiving, he  and his brethren."