2.NounThe widow of the holder of a title (usually a member of the peerage or a baronet); used in combination with the title she held during her husband's lifetime."the Earl and Countess of Whiteacre, and the Earl's mother, the dowager Countess of Whiteacre; Sir George Sitwell, Bt. and Lady Sitwell, and Sir George's mother, the dowager Lady Sitwell"