FOUR HUNDRED, in the United States, the expression popularly used to denote the inner circle of highest society. The term originally applied to New York city society and is said to have arisen in 1892 when Mrs. William Astor asked Ward McAl lister, a celebrated leader of society in New York city, to assist her in cutting down the invitation list of her annual ball to 400 persons as that was as many as her ballroom would accommodate. McAllister, who held a unique though self-appointed position as directing executive of New York society functions at that time, was heard to remark afterward at one of his clubs that there were really only 400 people living in New York city who had any claim to be called "society." The remark was repeated and spread rapidly until newspapers and magazines were full of discussions on it. From that time on the term became commonly used. It has, however, lost all meaning in recent years. There is no New York society in McAllister's sense of the term. There are scores of social groups and levels but no hierarchy.