The inner temple, the sanctuary — the dwelling place of God. Distinguished from hieron (the entire temple complex), naos specifically means the sacred inner chamber where God's presence dwells. The NT applies it to Christ's body, the believer, and the church.
Jesus declared, 'Destroy this temple [naos], and in three days I will raise it up' (John 2:19) — speaking of His body. Paul tells believers, 'You are the temple of God, and the Spirit of God dwells in you' (1 Corinthians 3:16). The physical temple was destroyed in AD 70, but God's dwelling shifted from a building to a people. In Revelation's new Jerusalem, there is no naos — because God Himself is the temple (21:22).