TIME PERIODS       Name Period bicentennial 200 years biennial 2 years century 100 years day 24 hours decade 10 years centennial 100 years decennial 10 years half-century 50 years half-decade 5 years half-millennium 500 years hour 60 minutes leap year 366 days millennium 1000 years minute 60 seconds month 28-31 days Olympiad 4 years quadrennial 4 years quadricentennial 400 years quincentennial 500 years semicentennial 50 years sesquicentennial 150 years tricennial 30 years vicennial 20 years week 7 days year 365-6 days year 12 months year 52 weeks   Return to Table of Contents       ©2004 Math Matters, Inc., All Rights Reserved