The Greek verb anakephalaioomai means to sum up, bring to a head, or gather all things under one head. Occurring twice in the NT (Romans 13:9; Ephesians 1:10), it comes from kephalē (head) and describes the act of gathering many things under a single governing head or summary.
The most theologically weighty use of anakephalaioomai is Ephesians 1:10, where Paul describes God's eternal plan: to bring all things in heaven and earth under one head — Christ. This is the biblical metanarrative in a single word: the fractured, fallen cosmos is being 're-headed' in Christ. Everything scattered by the fall — relationships, creation, nations, time itself — is being gathered, unified, and restored under Christ's headship. Romans 13:9 uses it more simply: all the commandments are summed up in 'Love your neighbor as yourself.'