The Hebrew word is used in various senses in the Old Testament, as,

1. Any kinsman, and not a mere brother; e.g. nephew, ( Genesis 13:8 ; 14:16 ) husband, ( Solomon 4:9 )
2. One of the same tribe. ( 2 Samuel 19:13 )
3. Of the same people, ( Exodus 2:11 ) or even of a cognate people. ( Numbers 20:14 )
4. An ally. ( Amos 1:9 )
5. Any friend, ( Job 5:15 )
6. One of the same office. ( 1 Kings 9:13 )
7. A fellow man. ( Leviticus 19:17 )
8. Metaphorically of any similarity, as in ( Job 30:19 ) The word adelphos has a similar range of meanings in the New Testament.