From Anstey’s Doctrinal Definitions:
This is not an expression that is found in Scripture, but what it conveys certainly is. It is an expression that Bible teachers have given to a specific sphere on earth where much in prophecy will be played out—particularly in connection with the Roman beast.
There are actually three spheres on earth (areas of land) where prophecy will be fulfilled. These are concentric circles, each having a wider range, and each having a different degree of light from God, and therefore, a different level of responsibility to God. These are:
• The “land”—The portion of the earth that was promised to Abraham and his descendants—Israel’s full inheritance, covering about 300,000 square miles of land. (The KJV mistakenly translates this as the “earth” in many places, and therefore, the prophetic student will need to consult a more critical translation such as J. N. Darby’s—i.e. Isaiah 26:18; 28:22; Matthew 24:30, etc.) This is the smallest circle.
• The “earth”—The portion of the earth where the old Roman Empire once asserted its authority, and where the revived Roman Empire under the Beast will also have its territory in the future. It includes “the land” but also takes in Asia Minor and Western Europe. Some believe that since America has been largely populated by people who came out of Europe (Dan. 2:43), that the United States and Canada could be part of this sphere. This area is referred to by Bible teachers as “the prophetic earth,” or “the Roman earth,” or “the western prophetic earth.” It is alluded to 14 times in Revelation 8-9 in the expression, “the third part.” “The fourth part of the earth” is a restricted part of the prophetic earth—Western Europe (Rev. 6:8).
• The “world”—This is a broader sphere yet, covering the whole globe, taking in the outlying nations.
All three of these terms occasionally appear in one passage of Scripture—i.e. Isaiah 18:2-3; 24:1-6; 26:9-10, 18-19.