The Hebrew noun iy refers to an island, coastland, or maritime region. In the Old Testament, islands and coastlands represent the remotest inhabited places of the earth — the boundaries of the known world beyond which God's rule nonetheless extends.
The coastlands in prophetic literature represent the far reaches of the Gentile nations. Isaiah repeatedly calls the 'islands' and 'coastlands' to hear God's word and to wait for His law (Isaiah 42:4; 49:1; 51:5). This is a remarkably inclusive vision — God's redemption is not confined to Israel but reaches to the uttermost parts of the earth. The missionary vision of the New Testament (Acts 1:8 — 'to the ends of the earth') fulfills what the prophets saw: every island and coastland will hear the gospel and bow before the LORD.