"epiphaneia" is a compound word made up of "epi" and "phaino."
"phaino" is translated "to manifest" or "to show."
It is also translated "to shine" in reference to the sun, moon and lamps in Rev. 1:16; 21:23; John 5:35 and 2 Peter 1:19.
The root word "phaino" is used in Colossians 3:4 two times,
"When Christ , who is your life, appears, then you also will appear with him in glory."
"epiphaneia" means "manifestation" or "glorious appearance." It was used to speak of a glorious manifestation of a Greek god that appeared with striking splendor with the intention of bringing helpful intervention.
"epiphaneia" is used to denote the sudden and unexpected appearance of an enemy who is bringing the battle to their opponents. It also is used of a god bringing helpful intervention during the battle. "epiphaneia" began to be used more generally to refer to divine assistance. Josephus used the word as a synonym for the Greek word "parousia"
In the New Testament "epiphaneia" is used most often for the future appearing of Jesus.
"Then the lawless one will be revealed (apokalupto), whom the Lord Jesus will overthrow with thebreath of his mouth and destroy by the splendor of his coming." 2 Thessalonians 2:8
"I charge you to keep this command without spot or blame until the appearing of our Lord Jesus Christ, which God will bring about in his own time." 1 Timothy 6:14
"In the presence of God and of Christ Jesus, who will judge the living and the dead, and in view of his appearing and his kingdom, I give you this charge: PREACH the WORD! 2 Timothy 4:1, 8
"We wait for the blessed hope - the glorious appearing of our great Godand Savior, Jesus Christ." Titus 2:1