Catherine W. (Kitty) Dun, 85, widow of the Right Rev. Angus Dun, former Episcopal bishop of Washington, died in her sleep Tuesday at Goodwin House in Alexandria, where she had lived since her husband's death in 1971.

During her episcopate here from 1944 to 1962, Mrs. Dun had been active in many Philanthropies. She had served as head of the residential unit of the old Community Chest Federation campaign. She also had been on the board of the former Washington Home for Incurables (now the Washington Home) and the YWCA. She had served on the women's boards of several Episcopal organizations affiliated with Washington Cathedral.

These included St. Albans School for Boys, National Cathedral School, the College of Preachers, the National Cathedral Association and All Hallow's Guild.

Mrs. Dun was born in Salem, Mass. She graduated from Radcliffe College in 1915 and was married a year later to Angus Dun, then a divinity student at Episcopal Theological School in Cambridge, Mass.

After World War I, she went to Britain with her husband and studied at the University of London and the University of Edinburgh. She made a special study of the Old and New Testaments and later put biblical stories into plays for children.

The Duns returned to Cambridge in 1920, when Bishop Dun joined the faculty of Episcopal Theological School. He was dean of the school when he was appointed to the Washington bishopric.

While they were in England, the Duns took up bicycling, which they continued during many of their years in Washington.

She is survived by two sons, the Rev. Angus Dun Jr., of Greenbrae, Calif., and Dr. Alan A., of Hartford, Conn.; three sisters, Mary H. Pew and Althea Barnard, both of Rockport, Mass., and Harriet Garfield, of Concord, Mass., nine grandchildren and five great-grandchildren.

The family suggests that expressions of sympathy may be in the form of contributions to the Angus Dun Memorial Fund at Washington Cathedral.