The incantation "Crucio" seems to be a reference to Roman crucifixion, which postdates Atlantis by several thousand years according to Plato's dating. There are probably lots of other examples of recent words in magic.
Could you clarify what point you are trying to make with this observation?
As for trying to draw inferences from canon incantations, that way madness lies. It seems beyond reasonable doubt that JK Rowling just used pseudo-Latinish words that fit the desired meaning, as is not unusual for a certain kind of children's fantasy story. There's little to indicate that she chose them based on some deeper historical or other reasoning.
For what it's worth, the Harry Potter Wiki claims that the Cruciatus Curse was invented in the Early Middle Ages, though it does not cite its sources.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 98. The previous thread is at nearly 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system.
Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: