Definition of "quinquennial" []

• Happening once every five years. (adjective)
• Lasting for five years. (adjective)
• A fifth anniversary. (noun)
• A period of five years. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "This festival was celebrated with spectacles and games of various kinds, which were called the quinquennial games, from the circumstance that the period for the celebration of them recurred once in five years."
• "The general authority given to bishops directly by the pope, in the so-called quinquennial faculties, may be delegated by them to others since the Decree of 14 December, 1898 (Acta S."
• "All but four countries in the world are meeting in New York this month at the quinquennial Non-Proliferation Treaty Review Conference to discuss the treaty's effectiveness."