* A misspelling: Could it be a typo for another word?
* A code or abbreviation: Is it used in a specific context or field?
* Made-up: Perhaps it's a made-up word for a fictional purpose.
To help me understand, please provide more context:
* Where did you see this word?
* What was the situation or conversation surrounding it?
With more information, I can help you decipher the meaning of "LNGEDNA".