determine

To discover or establish accurately and definitively, often through investigation, calculation, or logical reasoning. It also means to decide officially or conclusively, especially after consideration or with authority.

• Scientists are working to determine the exact cause of the new phenomenon. — This means they are trying to find out precisely what causes it.
• The committee will determine the new regulations by the end of the month. — This implies the committee will make a final, official decision on the regulations.
• Your effort will ultimately determine your success in this project. — This shows how one factor can directly influence or decide the outcome of another.

While the common and modern noun form derived from this verb is 'determination', 'determine' as a standalone noun is an archaic or exceptionally rare usage in contemporary English. When it appears, it refers to the act or process of officially establishing something, or a formal decision or conclusion that has been reached. It typically does not convey the sense of 'firmness of purpose' or 'steadfastness' that is more commonly and directly expressed by 'resolve' or the everyday noun 'determination' itself.

• The court's final determine on the matter was published yesterday, though the term 'determination' is far more common in such contexts. — This refers to the court's conclusive decision.
• The precise determine of the artifact's age required advanced carbon dating techniques. — This refers to the act of establishing or finding out the artifact's age.