TEHRAN  It was hot in the car, so the young woman and her singing instructor got out for a breath of fresh air on a quiet side street not far from the antigovernment protests they had ventured out to attend. A gunshot rang out, and the woman, Neda Agha-Soltan, fell to the ground. “It burned me,” she said before she died.

The bloody video of her death on Saturday, circulated in Iran and around the world, has made Ms. Agha-Soltan, a 26-year-old who relatives said was not political, an instant symbol of the antigovernment movement.

Her death is stirring wide outrage in a society that is infused with the culture of martyrdom  although the word itself has become discredited because the government has pointed to the martyrs’ deaths of Iranian soldiers in the Iran-Iraq war to justify repressive measures.

Ms. Agha-Soltan’s fate resonates particularly with women, who have been at the vanguard of many of the protests throughout Iran.