chief executive

Short definition from Wiktionary

Noun

1. 1
   The president of the United States.
2. 2
   The head of government or head of state: The head of government of Hong Kong
3. 3
   The head of government or head of state: The head of government of Macau
4. 4
   The governor of a U.S. state.
5. 5
   Chief executive officer.