In Spanish 'Ocho' means 'eight', or 'Ocho' means 'eight' in English?
Solution 1:
As for your title, I think "Ocho means eight in Spanish" is correct.
I think this because:
This sentence is correct:
"Ocho" is the Spanish word for "eight." (or "Ocho is Spanish for eight")
But this:
"Ocho" is English for "eight."
is of course incorrect.
If you reword that sentence to include the word "means," I think it should follow the same pattern.
"Ocho" means "eight" in Spanish.
Solution 2:
Consider saying instead:
"Ocho is (the) Spanish for eight."