Sister sis'-ter ('achoth): Used repeatedly in the Old Testament of a female
(1) having the same parents as another; or
(2) having one parent in common, with another, half-sister (Genesis 20:12, Leviticus 18:9), and also
(3) of a female belonging to the same family or clan as another, so a kinswoman (Genesis 24:60, Job 42:11);
(4) also of a woman of the same country (Numbers 25:18).
(5) Figuratively, the two kingdoms, Israel and Judah, are sisters (Ezekiel 23:7).
(6) Confederate cities are conceived of as sisters (Ezekiel 16:45).
(7) 'Achoth is used of objects which go in pairs, as curtains, each `coupled to its sister' (Exodus 26:3, Exodus 26:6), and of wings in pairs (Ezekiel 1:9, Ezekiel 3:13);
(8) of virtues or conditions, with which one is closely related: "Say unto wisdom, thou art my sister" (Proverbs 7:4; compare Job 17:14);
(9) of a lover concerning his spouse, as a term of endearment (Song of Solomon 4:9, Song of Solomon 5:1, Song of Solomon 8:8).
In the New Testament, adelphe, used
(1) in sense of physical or blood kinship (Matthew 12:50, Matthew 13:56, Matthew 19:29, Luke 10:39, Luke 14:26, John 11:1, John 19:25, Acts 23:16);
(2) of fellow-members in Christ: "Phoebe, our sister" (Romans 16:1; see also 1 Corinthians 7:15, 1 Timothy 5:1, James 2:15);
(3) possibly, of a church, "thy elect sister" (2 John 1:13).
Edward Bagby Pollard