King, or king regnant, is the title given to a male monarch in a variety of contexts. The female equivalent is queen regnant, while the title of queen on its own usually refers to the consort of a king.
The term king may also refer to a king consort, a title that is sometimes given to the husband of a ruling queen, but the title of prince consort is sometimes granted instead.


The English term is derived from the Anglo-Saxon cyning, which in turn is derived from the Common Germanic *kuningaz. The Common Germanic term was borrowed into Estonian and Finnish at an early time, surviving in these languages as.
The English term "King" translates, and is considered equivalent to, Latin rēx and its equivalents in the various European languages. The Germanic term is notably different from the word for "King" in other Indo-European languages. It is a derivation from the term *kunjom "kin" by the -inga- suffix. The literal meaning is that of a "scion of the kin", or perhaps "son or descendant of one of noble birth".


The English word is of Germanic origin, and historically refers to Germanic kingship, in the pre-Christian period a type of tribal kingship. The monarchies of Europe in the Christian Middle Ages derived their claim from Christianisation and the divine right of kings, partly influenced by the notion of sacral kingship inherited from Germanic antiquity.
The Early Middle Ages begin with a fragmentation of the former Western Roman Empire into barbarian kingdoms. In Western Europe, the kingdom of the Franks developed into the Carolingian Empire by the 8th century, and the kingdoms of Anglo-Saxon England were unified into the kingdom of England by the 10th century.
With the breakup of the Carolingian Empire in the 9th century, the system of feudalism places kings at the head of a pyramid of relationships between liege lords and vassals, dependent on the regional rule of barons, and the intermediate positions of counts and dukes. The core of European feudal manorialism in the High Middle Ages were the territories of the former Carolingian Empire, i.e. the kingdom of France and the Holy Roman Empire.
In the course of the European Middle Ages, the European kingdoms underwent a general trend of centralisation of power, so that by the Late Middle Ages there were a number of large and powerful kingdoms in Europe, which would develop into the great powers of Europe in the Early Modern period.
Currently, fifteen kings are recognized as the heads of state of sovereign states.
Most of these are heads of state of constitutional monarchies; kings ruling over absolute monarchies are the King of Saudi Arabia, the King of Bahrain and the King of Eswatini.
Harald V King of NorwayGlücksburgkongeKingdom of Norway11th c.
Carl XVI Gustaf King of SwedenBernadottekonungKingdom of Sweden12th c.
Felipe VI King of SpainBourbonreyKingdom of Spain1978 / 1479
Willem-Alexander King of the NetherlandsOrange-NassaukoningKingdom of the Netherlands1815
Philippe King of the BelgiansSaxe-Coburg and Gothakoning / roi / KönigKingdom of Belgium1830
Salman King of Saudi ArabiaSaudملك malikKingdom of Saudi Arabia1932
Abdullah II King of JordanHashimملك malikHashemite Kingdom of Jordan1946
Mohammed VI King of MoroccoAlaouiملك malikKingdom of Morocco1956
Hamad bin Isa Al Khalifa King of BahrainKhalifaملك malikKingdom of Bahrain1971
Vajiralongkorn King of ThailandChakriกษัตริย์ kasatKingdom of Thailand1782
Jigme Khesar Namgyel Wangchuck King of BhutanWangchuckའབྲུག་རྒྱལ་པོ་ druk gyalpoKingdom of Bhutan1907
Norodom Sihamoni King of CambodiaNorodomស្ដេច sdacKingdom of Cambodia1993 / 1953
Tupou VI King of TongaTupouking / tu'iKingdom of Tonga1970
Letsie III King of LesothoMosheshking / morenaKingdom of Lesotho1966
Mswati III King of EswatiniDlaminingwenyamaKingdom of Eswatini1968