King
In short
A male monarch who holds sovereign power over a nation or territory. This role can range from an absolute ruler with total control to a constitutional monarch with limited powers.
In plain words
A king is the highest-ranking male leader in a kingdom. In some countries, he makes all the laws, while in others, he is a symbol with no real political power.
A simple example
A constitutional king might attend official ceremonies and represent his country, but the elected parliament actually runs the government.
Why it matters
The title defines the structure of a nation's leadership and its historical traditions. It determines whether power is held by one person or shared with a government.
Easy to mix up
Do not confuse a king with an emperor, who typically rules over a collection of many different states or territories.