The Catholic Church uses a number of complex words to denote specific teachings as well as events that happened in the Bible.
These words are translated into English in the best way possible, though translations cannot fully bring about the full weight of what they are referring to.
Transfiguration is one such word that is helpful, but at the same time has a complex meaning behind it.
Jesus' transfiguration
The Gospel of Matthew provides us with the details of Jesus' tranfiguration:
And after six days Jesus took with him Peter and James and John his brother, and led them up a high mountain apart. And he was transfigured before them. (Matthew 17:1-2)
The Catholic Encyclopedia explains how "St. Matthew and St. Mark express this phenomenon by the word metemorphothe [in Greek], which the Vulgate renders transfiguratus est [in Latin]."
What's interesting is how the Greek word is the root of the English "metamorphosis" and "metamorphize."
In this sense, while Jesus remained "himself," he truly "transfigured," changing his appearance in such a way that made him radically different to human eyes.
The Gospel writers do provide a description of his appearance:
[H]is face shone like the sun, and his garments became white as light. (Matthew 17:3)
The Catholic Encyclopedia states that, "This dazzling brightness which emanated from His whole Body was produced by an interior shining of His Divinity."
Like nothing seen before
Furthermore, "By this glorious manifestation the Divine Master, who had just foretold His Passion to the Apostles (Matthew 16:21), and who spoke with Moses and Elias of the trials which awaited Him at Jerusalem, strengthened the faith of his three friends and prepared them for the terrible struggle of which they were to be witnesses in Gethsemani, by giving them a foretaste of the glory and heavenly delights to which we attain by suffering."
Essentially Jesus "lifted the veil" of his humanity to shine forth his divinity.
What Peter, James and John saw was a Jesus fully glorified, in such a splendor that words are difficult to express it.
Transfiguration was the best word we could come up with to describe what happened that day on Mount Tabor. It isn't perfect, but when you dig a little deeper, you can begin to understand that what the apostles saw was truly astonishing and like nothing they had ever seen.
