1. a title sometimes used by the wife of a British king after his death, if she is the mother of the next king or queen.
2. Queen Elizabeth (1900–2002), the widow (= woman whose husband has died) of King George VI . She was born Elizabeth Bowes-Lyon, the youngest daughter of the Earl of Strathmore, and married George in 1923, becoming the Duchess of York. He became king in 1936, so she then became known as Queen Elizabeth. When her daughter became Queen Elizabeth II , she became known as the Queen Mother. She was very popular with the people of Britain.