The Greek verb anakephalaiomai means "to sum up," "to bring together under one head," or "to recapitulate." It combines ana- (up/again) + kephalaion (sum, main point, head). It appears in Romans 13:9 (the law summed up in love) and Ephesians 1:10 (all things summed up in Christ).
The two appearances of anakephalaiomai reveal the grand unity of God's redemptive plan. In Romans 13:9, all commandments are summed up in love for neighbor — love fulfills the law. In Ephesians 1:10, the eternal divine plan is to sum up all things in Christ — all of history, all of creation, all of humanity — gathered under His lordship. Christ is the anakephalaion of all things: He is the unifying center of reality itself.