Lady Clementine Spencer-Churchill, the widow of former British Prime Minister Sir Winston Churchill, died yesterday after a heart attack at her apartment in London. She was 92.

She married a man who many came to regard as the greatest of his times, and theirs was a celebrated marriage. It gave her life its definition: she was the wife of Winston Churchill. He himself acknowledge his debt in a famous tribute.

"My marriage was much the most fortunate and joyous event which happened to me in the whole of my life," he wrote. "For what can be more glorious than to be united in one's walk through life with a being incapable of an ignoble thought."

Lady Spencer-Churchill once said: "If you find yourself in competition with men, never become aggressive in your rivalry. You will gain far more by quietly holding to your convictions, but even this must be done with art and above all, with humor."

For most of the 57 years they were together until Churchill's death in 1965, she practiced her "art" in the relative privacy of her family and a small circle of friends."It does not worry me to be in the background," she once said. "He's got his work to do."

It was not until her husband became Prime Minister in World War II and led his nationa through its "finest hour," that she became widely known in her own right. She worked for the Red Cross and for Russian relief. She stayed in London during the "blitz" and visited neighborhoods where the German bombing had been worst. She flashed her wit: "I have made up my mind to ignore all this completely," she remarked to a friend.

She earned the esteem and affection of the British people. Three British sovereigns honored her for her own work. King George V made her a commander of the Order of the British Empire for the contributions during World War I. King George VI elevated her to the rank of Dame of that Order for her services in World War II, dame being the equivalent of a knight. In 1965, Queen Elizabeth II created her Baroness Spencer-Churchill-ill of Chartwell, Chartwell being the country home the Churchills occupied 20 miles south of London for many years.

The Queen sent private condolences to the family yesterday on Lady SPencer-Churchill's death.

Earlier this year, when it bacame known that Lady Spencer-Churchill was selling some of the pictures her husband had painted to help meet her expenses, a move was started to provide her with an allowance to cover her needs. She would not hear of it.

"I greatly deplore any idea that* either special legislation or an appeal should be initiated," she said.

So said Lady Clementine Ogilvy Hozier Spencer-Churchill, descendent of the Earls of Airlie in the Scottish peerage.

John Colville, one of Churchill's private secretaries, described her as a woman of temperament and generosity, of strong character and common sense. Most of all, he described her as woman of sympathy - sympathy not only for her husband's legendary folbles and eccentricities, for which she provided a background of calm and stability, but sympathy for all those in need, of whatever station in life.

"It was a challenge to be married to the greatest man of the century," Colville wrote a year after Churchill's death. "It was a triumph to be constantly loving and admiring yet never to lose her own independence of judgement, even when it conflicted with his, or to be uncritical of his actions.Winston Churchill would certainly have left his mark whomever he had married, but it is questionable whether any other wife would have contributed quite so much to his success, his happiness and his popularity."

Mrs. Eleanor Roosevelt, who had special knowledge in such matters, would have agreed with this assessment. In an introduction to "My Darling Clementine," a popular biography of Lady Spencer-Churchill published by Jack Fishman in 1963. Mrs Roosevelt wrote:

"It would of course be very hard to ruin a man of the stature of Winston Churchill, very hard. But you could make it more difficult for him to do his work; there is no question about that."

Mrs. Roosevelt added. "I sometimes wonder whether people realize the price the wife and family of a man in public life have to pay."

In considering the grandeur of Churchill's career, it is easy to forget that money was frequently in short supply for him in relation to his tastes (a friend once remarked that the great man was "easily satisfied with the best").

Part of the price for Lady SPencer-Churchill was making do on limited means. Colville, the former private secretary, recalled that "she sufferd acutely from (Churchill's) unpredictable habits, as when he would invite numbers of political friends to dine at a moment's notice, oblivious of the shortage of food, money and servants."

John Spencer Churchill, a nephew, once said: "At Chartwell it never ceases to amaze me how my aunt copes with running the place. Her role is that of an A.D.C. Extraordinary and Super Quartermaster to the greatest of Captains General. For Chartwell, and indeed any other house my uncle occupies, it is not only a kind of military headquarters, but a large factory filled with high-powered executives. To see that this factory runs smoothy with meals at odd hours for visiting experts and relays of secretaries working through the night calls for tremendously detailed organization."

More to the point than these hectic details, however, was the closeness of the Churchills' marriage. She listened as he practiced his speeches. He would glance at her as she sat in the gallery of House of Commons as he spoke during important debates. She would play cards with him into the early morning hours.

She encouraged him when his ambitions lay in pieces around him. In 1915, after he had been forced to step down as First Lord of the Admiralty in the wake of the failure of the British offensive against the Turks at Gallipoll, and was commanding a battalion of the Royal Scots Fusiliers on the Western Front, she wrote, "Patience is the only grace you need."

And, on another occasion in the same period, she wrote: "Try not to brood too much. I would be so unhappy if your naturally open and unsuspicious nature became embittered. If you are not killed, as sure as the day follow night, you will come into your own again."

Before the end of the war, Churchill had been recalled to the Cabinet as minister of munitions. He remained a power in politics until the early 1930s, when he broke with the leadership of the Conservative Party, of which he then was a member, and began a self-exile from the seats of power. It was during these years that Churchill began to attack the policies of appeasing Hitler and Mussolini that were being advocated by Prime Minister Neville Chamberlain. He did not return to high office until the outbreak of World War II.

When the conflict ended in 1945. Churchill said of his wife: "It would have been impossible for any ordinary man to have got through what I have had to get through in peace and war without her devoted aid."

Clementine Ogilvy Hozier was born April 1, 1885, the daughter of Sir Henry Hozier, a cavalry colonel, and Lady Blanche Ogilvy Hozier, daughter of the Seventh Earl of Airlie. The marriage of her parents was unsuccessful and she was brought up by her mother in England and was competent in several other foreign languages.

She and Churchill himself the grandson of a Duke of Marlborough, met in 1908. She was 23 and he was 10 years older and already a luminary on the political scene. Their courtship was brief and they were married in the same year at St. Margaret's Church, Westminister, London. The entire Cabinet atended the wedding, which was one of the social landmarks of the year.

Churchill described his bride as "the reigning Beauty, tall and stately, with delicate features and lovely gray eyes."

They had five children. Randolph, their only son, died of cancer in 1963. Their eldest daughter, Diana, died of an overdose of sleeping pills in 1963. Sarah Churchill went on to a career on the stage. Mary was married to Sir Christopher Soames. Marigold died of pneumonia when she was 2 years old.

Lady Spencer-Churchill stayed by her husband's side during the illness that ended in his death. She had acted in his stead on numerous occasions during his life - campaigning for him, receiving the Nobel Peace Prize in his behalf in 1953, travelling to the Soviet Union in the closing days of World War II. When he died, she was conspicious in the dignity and grace with which she led the nation and the world in honoring him.

In the years following, she made few public appearances. On her 89th birthday in 1974, she attended the launching of a fund-raising drive for the Churchill Memorial Trust. The purpose was to raise 1 million pounds in the form of one-pound donations from 1 million people and to assist needy students.

Lady Spencer-Churchill's grandson, Winston Churchill, a Conservative member of Parliament, said his grandmother had been stricken while lunching with her private secretary Nonie Chapman. He said Lady Spencer-Churchill had been troubled by arthritis and failing vision in recent years, but that she had no history of heart trouble.

Young Churchill said his grandmother had been looking forward to an afternoon drive at the time she suffered the heart attack. He said private services would be held and that she would be buried next to her husband in the churchyard at Bladon, the village in Buckinghamshire where Blenheim Palace is located. Blenheim is the home of the Dukes of Marlborough and Churchill's birthplace.

Churchill often called his wife "my darling Clemmie." Last winter, a pot of flowers was placed next to the Churchill memorial stone in Westminster Abbey. The card said, "With love, Clemmie."