(countable) A king is the male leader of a country and whose son will probably lead the country.
Following the death of James I, Charles I became King of England, in 1625
(countable) (idiomatic) A powerful or influential person.
Howard Stern styled himself as the "king of all media".
(countable) (chess) One of the playing pieces in chess; it may move only once square per move in any direction, but cannot move into check (threat of attack).
(countable) A playing card with the image of a king on it.

Noun