Noun
1. a male sovereign; ruler of a kingdom
2. a competitor who holds a preeminent position
3. a very wealthy or powerful businessman;
"an oil baron"4. preeminence in a particular category or group or field;
"the lion is the king of beasts"5. a checker that has been moved to the opponent's first row where it is promoted to a piece that is free to move either forward or backward
6. one of the four playing cards in a deck bearing the picture of a king
7. (chess) the weakest but the most important piece