What does subternal mean?

"Subternal" is not a recognized word in standard English. It's likely a misspelling or a made-up word.

If you're looking for a related term, you might be thinking of:

* Subterranean: This refers to something located beneath the surface of the earth.

* Internal: This refers to something located inside the body or a structure.

Please provide more context about where you encountered the word "subternal" so I can help you find the correct term.