From Longman Dictionary of Contemporary EnglishQueen MotherˌQueen ˈMother noun [singular] PGOthe mother of the ruling king or queenQueen Mother, thethe Queen MotherQueen Mother, the (1900–2002) the mother of the British Queen Elizabeth II, whose official title was Queen Elizabeth, the Queen Mother. She was one of the most popular and respected members of the royal family, and was thought of as a kind and caring person. She was known to be very interested in horse racing, and she was often called, ‘the Queen Mum’ in British popular newspapers.
