The "Last Judgment" is not a biblical term, but is taken from church tradition. Augustine, in The City of God, Book XX, states the following:
And when we speak of God's judgment, we add the word last or final for this reason, because even now God judges, and has judged from the beginning of human history, banishing from paradise, and excluding from the tree of life, those first men who perpetrated so great a sin. Yes, He was certainly excercising judgment also when He did not spare the angels who sinned, whose prince, overcome being, seduced men after being himself seduced. Neither is it without God's profound and just judgment that the life of demons and men, the one in the air, the other on earth, is filled with misery, calamities, and mistakes. . . . He judges, too, not only the mass, condemning the race of devils and the race of men to be miserable on account of the original sin of these races, but He also judges the voluntary and personal acts of individuals. . . . And men are punished by God for their sins often visibly, always secretly, either in this life or after death . . . In this book, then, I shall speak, as God permits, not of those first judgments, nor of these intervening judgments of God, but of the last judgment, when Christ is to come from heaven to judge the quick and the dead.