* A misspelling: Perhaps it was meant to be "American" or a similar word.
* A made-up word: Someone may have created it for a specific purpose, like a brand name or a fictional term.
* A regional term: There's a chance it's used in a specific community or dialect.
To understand the meaning, we need more context. Could you please provide:
* The source of the word: Where did you encounter it? (book, website, conversation, etc.)
* The surrounding text: What was the word used in relation to?
With more information, I can help you figure out the intended meaning of "Amerigen."