What does the prefix solu mean?

The prefix "solu-" is not a common prefix in English. It is likely that you are thinking of a different prefix, such as:

* "sol-": This prefix, meaning "sun" or "solar", is found in words like "solar" and "solstice".

* "solv-": This prefix, meaning "loosen" or "dissolve", is found in words like "solve" and "soluble".

If you can provide more context or the word you are trying to decipher, I may be able to help you further.