My company is having contracts drafted in both English and Japanese and we want to have the English version take priority over the Japanese. Is there a specific legal term for this structure?
I don't know of a specific legal term but such clauses are quite common in contracts which consist of more than one document. The English words "priority", "prevail" and "precedence" have the meaning you want, however, "precedence" runs the risk of being confused with "precedent" which does have a very specific legal meaning.
A clause similar to:
If there is any inconsistency or ambiguity between the English and Japanese language versions of the contract, the English version shall prevail.
You need to make very sure that this clause can be translated unambiguously into Japanese!