The Green Line refers to the boundary between Israel and the West Bank as demarcated by the 1949 Armistice agreement. The Armistice Line ended hostilities between Israel and Arab countries in the 1948 War of Independence and demarcated the borders between the West Bank and Gaza Strip as recognized by the international community. Israel does not officially recognize the Green Line, as it does not officially recognize a border between Israel and the West Bank.
Similarly, the Seam Line refers to the border between Israel and the West Bank, but is more typically used in reference to areas between towns and cities inside Israel and Palestinian areas in the West Bank.