Doesn't that get confusing with the "@" sign often being called "kanelbulle" (cinnamon bun, https://commons.wikimedia.org/wiki/File:Kanelbulle.jpg for the non-Swedes :-) )
Actually is snail another word from Danish that English adopted?
Update: not even close, not on your Nellie even.
“In Danish, it is snabel-a ('elephant's trunk A').”
https://en.wikipedia.org/wiki/At_sign
Apologies I seem to find rabbit holes within rabbit holes, Not on your Nellie being Cockney rhyming slang, just tied into Nellie the Elephant:
https://www.urbandictionary.com/define.php?term=not%20on%20y...
Likely due to common roots rather than transplant. You'll find a similar word in the other Germanic languages.
Snabel-a in Danish is correct, you'll hear it all the time when there's an email address.