William

[wil-yuh m] /ˈwɪl yəm/
noun
1.
a word formerly used in communications to represent the letter W.
2.
a male given name: from Germanic words meaning “will” and “helmet.”.

William I

noun
1.
("the Conqueror") 1027–87, duke of Normandy 1035–87; king of England 1066–87 (son of Robert I, duke of Normandy).
2.
Also, Willem I. (William I of Orange"the Silent") 1533–84, Dutch leader, statesman, and revolutionary leader born in Germany: prince of Orange 1544–84; count of Nassau 1559–84; 1st stadholder of the United Provinces of the Netherlands 1578–84.
3.
Also, Wilhelm I. (Wilhelm Friedrich Ludwig) 1797–1888, King of Prussia 1861–88; emperor of Germany 1871–88 (brother of Frederick William IV).

William II

noun
1.
(William Rufus"the Red") 1056?–1100, King of England 1087–1100 (son of William I, duke of Normandy).
2.
Also, Wilhelm II. (Frederick Wilhelm Viktor Albert) 1859–1941, king of Prussia and emperor of Germany 1888–1918.

William III

noun
1.
(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.

William IV

noun
1.
("the Sailor-King") 1765–1837, king of Great Britain and Ireland 1830–37 (brother of George IV).
British Dictionary definitions for William

William

/ˈwɪljəm/
noun
1.
known as William the Lion. ?1143–1214, king of Scotland (1165–1214)
2.
Prince. born 1982, Duke of Cambridge, first son of Prince Charles and Diana, Princess of Wales. In 2011 he married Kate Middleton (born 1982); their son, Prince George, was born in 2013

William I

noun
1.
known as William the Conqueror. ?1027–1087, duke of Normandy (1035–87) and king of England (1066–87). He claimed to have been promised the English crown by Edward the Confessor, after whose death he disputed the succession of Harold II, invading England in 1066 and defeating Harold at Hastings. The conquest of England resulted in the introduction to England of many Norman customs, esp feudalism. In 1085 he ordered the Domesday Book to be compiled
2.
known as William the Bad. 1120–66, Norman king of Sicily (1154–66)
3.
known as William the Silent. 1533–84, prince of Orange and count of Nassau: led the revolt of the Netherlands against Spain (1568–76) and became first stadholder of the United Provinces of the Netherlands (1579–84); assassinated
4.
1772–1843, king of the Netherlands (1815–40): abdicated in favour of his son William II
5.
German name Wilhelm I. 1797–1888, king of Prussia (1861–88) and first emperor of Germany (1871–88)

William II

noun
1.
known as William Rufus. ?1056–1100, king of England (1087–1100); the son of William the Conqueror. He was killed by an arrow while hunting in the New Forest
2.
known as William the Good. 1154–89, last Norman king of Sicily (1166–89)
3.
1792–1849, king of the Netherlands (1840–49); son of William I
4.
German name Kaiser Wilhelm. 1859–1941, German emperor and king of Prussia (1888–1918): asserted Germany's claim to world leadership; forced to abdicate at the end of World War I

William III

noun
1.
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

William IV

noun
1.
known as the Sailor King. 1765–1837, king of the United Kingdom and of Hanover (1830–37), succeeding his brother George IV; the third son of George III
Word Origin and History for William

masc. proper name, from Old North French Willaume, Norman form of French Guillaume, of Germanic origin (cf. Old High German Willahelm), from willio "will" + helma "helmet." After the Conquest, the most popular given name in England until supplanted by John.