"The Elect" are the individuals who will be saved and enjoy eternal life.
John Calvin (1509-64) was an advocated of predestination, he believed predestination was God’s eternal decree regarding the individuals who will be saved and enjoy "eternal life" after death (THE ELECT) and the ones who will be in eternal condemnation. According to Calvin, God made this decision even long gone before the world was created, and humans can not do anything to change this decree.