The phrase "a definitive role" is correct and usable in written English.
It can be used when discussing a clear and unambiguous position or function that someone or something has in a particular context.
Example: "In the project, she played a definitive role in shaping the overall strategy and direction."
Alternatives: "a crucial role" or "a key role".
Network television played a definitive role, but those were very different times.
What is newsworthy is that socioeconomic status plays such a definitive role in deciding who gets to have a good time in the bedroom and who doesn't.
For example evaporation has a definitive role in the performance of soil covers widely used in mining and landfill applications for environmental protection.
The first, Ψ1, is known to play a definitive role in the energy transport from the solar wind into the magnetosphere-ionosphere-atmosphere system, but the role of Ψ02 in this transport is not well known.
Even if he fails to secure the role of prime minister, Binyamin Netanyahu, the Likud leader, will play a definitive role in formulating the next government's security and foreign policies.
"He has a definitive role of what we understand as today's Seattle, which is about technology, about real estate and about a distinctive local culture with international visibility," said Margaret O'Mara, a history professor at the University of Washington.
Neutrophils pre-incubated with each inhibitor demonstrated significant reductions in NET release following OO extract stimulation (p ≤ 0.01, Fig. 3A), confirming a definitive role for each of these enzymes in OO extract-induced NET release.
Astrocyte swelling plays a definitive role in the development of cytotoxic brain edema.
Acquiring firms have a definitive role only in the former mode of divestiture, but not in the latter.
Using DNA microarrays and knock-out mouse studies, we showed that CCR5 plays a definitive role in the development of ovalbumin-induced allergic airway inflammatory disease.
Infection control teams play a definitive role in antibiotic AMS programs by assisting with prompt detection of MDROs and promoting compliance with standard and transmission-based precautions.
