1. [n]  the act of transforming so as to exalt or glorify
2. [n]  a striking change in appearance or character or circumstances; "the metamorphosis of the old house into something new and exciting"
3. [n]  (New Testament) the sudden emanation of radiance from the person of Jesus
4. [n]  (Christianity) a church festival held in commemoration of the Transfiguration of Jesus

TRANSFIGURATION is a 15 letter word that starts with T.