Watertown - Mrs. Dorothy A. Smith, of Watertown, died Friday, March 24, 2006 at Mount Auburn Hospital, Cambridge. She was 90. Born in Dorchester, a daughter of the late Harry and Victoria (Titus) Dinjian, Dorothy had lived in Watertown for most of her life. Until her retirement, she had worked for many years for the Raytheon Company. The wife of the late Guy Smith and sister of the late Helen and Leo Dinjian and Mary Kerr, Dorothy is survived by several friends. Funeral services will be held at 11 a.m. Tuesday in The Joyce Funeral Home, 245 Main Street (Rte. 20), Waltham. Burial will be private. Visitation will be held prior to the service from 10 to 11 a.m.