William III noun
- William III of Orange, 1650–1702, stadholder of the United Provinces of the Netherlands 1672–1702; king of England 1689–1702, joint ruler with his wife, Mary II.
British Dictionary definitions for william iii William III noun
- known as William of Orange. 1650–1702, stadholder of the Netherlands (1672–1702) and king of Great Britain and Ireland (1689–1702). He was invited by opponents of James II to accept the British throne (1688) and ruled jointly with his wife Mary II (James’ daughter) until her death in 1694