Could you please provide more context or information about where you encountered this term? Perhaps it's related to:
* A specific field or subject: If you saw it in a technical document or academic paper, knowing the subject area might help identify the intended meaning.
* A particular language: If it's from a foreign language, knowing the source language could aid in translation.
* A personal context: If you heard it from someone, maybe they meant something else entirely and you can ask for clarification.
Once you provide more details, I might be able to help you understand what "root turb" might refer to.