lieutenant governor

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An elected official ranking just below the governor of a state in the United States.
• noun The nonelective chief of government of a Canadian province.

from The Century Dictionary.

• noun An officer authorized to perform the functions of a governor in case of the absence, disability, or death of the latter, or in a subordinate governorship.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Canada, government The representative of the Crown in the provincial legislatures of Canada.
• noun US, government The next-in-line to the chief executive of a primary political division of the United States of America, such as a state, second to the governor.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an elected official serving as deputy to the governor of a state of the United States