Prophecy refers to things or events spoken of in the Bible by prophets of God which have a fulfillment at a particular time appointed by God, such as the virgin birth of Jesus Christ (Isaiah 7:14), His earthly ministry (Isaiah 42:1-4), and His death on the cross (Psalm 22). Peter the apostle says that:

no prophecy of Scripture is of any private interpretation, for prophecy never came by the will of man, but holy men of God spoke as they were moved by the Holy Spirit. (2nd Peter 1:20-21)

Throughout the entire LEFT BEHIND series, there are events prophesied in the Bible that have had their fulfillment in the time period of the series, such as the Rapture, the Tribulation, and the Second Coming.