People talk about the role of chairman or chief executive as though these are clear definitive roles.

"Everybody seemed to take up a definitive role."

Religion still plays a central and definitive role in the life of many of its people.

Kramer argues that recent scientific research actually shows a definitive role for serotonin deficiency in depression.

From a letter of credit standpoint, however, the receipt message can also play a more definitive role.

Organic unity lacked a true definitive role or theme in literary history until the principle was adopted by Aristotle.

Culture plays a definitive role in the formation of human behavior.

"It is the definitive role for a woman in the musical theater," said Julie Andrews, who was 20 years old when she originated the part.

But in all cases there are the clear personal features which play a definitive role in his work.

Many consider this to have been a "definitive role" for Whitaker.