The widow of a peer, eg the Dowager Countess of Somewhere. The term was not added to a woman’s title unless and until the new (male) holder of the title married. For example, if the new Earl of Somewhere, the son of the late earl, is a young man when he inherits the title and has no wife, his mother continues to be styled Countess of Somewhere. When he marries, his wife takes that title and his mother becomes the Dowager Countess. The term is also sometimes used informally, and disparagingly, to refer to an older woman of the upper classes.