What does the prefix manu means?

The prefix "manu" is not a standard prefix in the English language. It is possible you are thinking of "man" which does have a few meanings depending on context:

* Human being: This is the most common meaning, referring to a person.

* Male person: It can also specifically refer to a male individual.

* Part of a word: It can be part of a larger word, such as "manhood," "mankind," or "manly."

If you have a specific word in mind, please provide it so I can help you further.