From meta (change) and morphē (form). Means to transform, to change in form — the root of the English word 'metamorphosis.' Used of Jesus' transfiguration on the mountain and of the believer's progressive transformation into Christ's likeness.
This word describes the most dramatic visible transformation in the Gospels: Jesus was transfigured before Peter, James, and John, His face shining like the sun (Matthew 17:2). But its most pastorally significant use is in Romans 12:2, where Paul commands believers to 'be transformed by the renewing of your mind.' In 2 Corinthians 3:18, believers are being transformed into Christ's image 'from glory to glory.' This is sanctification — the Spirit's work of progressively making believers like Christ.