Time required for the Earth to travel once around the Sun, slightly less than 365 days. This fractional number makes necessary the periodic adjustment of days in any calendar that is to be kept in step with the seasons. In the Gregorian calendar, a common year contains 365 days, and every fourth year is a leap year of 366 days except for any year that is divisible by 100 but not divisible by 400 (e.g., 1900 was not a leap year).

This entry comes from Encyclopædia Britannica Concise.
For the full entry on year, visit

Seen & Heard

What made you look up year? Please tell us what you were reading, watching or discussing that led you here.