atavachron → αταβαχρόνιο
"Ah, this is the atavachron."
"Interesting nomenclature. How does it work?""
– Mr. Atoz and Spock, 2269 ("All Our Yesterdays")
The Atavachron was a computer device utilized on the planet Sarpeidon to prepare its inhabitants for use of a time portal, by altering the user's cellular structure and brain patterns for survival in their selected time period. Without processing by the atavachron, one could only survive in that time period for a matter of hours. With processing, the user could survive in 'their' new time, but they would die instantly if they were to attempt to return through the portal.
https://memory-alpha.fandom.com/wiki/Atavachronhttps://www.youtube.com/watch?v=U3Mc9d5IQGYStar Trek - Time Portal