A house, a household, or a family — the physical dwelling and the people who inhabit it. Oikos extends to the 'house of God' (the temple/church) and the 'household of faith.' It represents belonging, identity, and community.
The 'household of God' metaphor shapes NT ecclesiology: believers belong to God's oikos (Ephesians 2:19). Household baptisms in Acts (Lydia, the Philippian jailer) suggest that faith was communal, not merely individual. Jesus said, 'In my Father's house are many rooms' (John 14:2) — heaven itself is described as home. The NT vision is that God is building a spiritual oikos with living stones (1 Peter 2:5).