Katoptrízomai (κατοπτρίζομαι) means to behold as in a mirror, to reflect like a mirror. Ancient mirrors were polished metal. Combines kata (fully) + optron (mirror). Appears once in the NT.
Second Corinthians 3:18: 'we all, with unveiled faces contemplating the Lord's glory, are being transformed into his image with ever-increasing glory.' Moses' face radiated glory after being with God; now in Christ, the veil is removed and believers behold God's glory. As we behold, we become. This is the central mechanism of sanctification: prolonged, attentive beholding of Christ transforms us into His likeness. Bible reading, prayer, and worship are not optional — they are how God does His transformative work.