What is a leap year? What is a common year?

What is a leap year? What is a common year?

A leap year contains 1 extra day, February 29th, over an ordinary year, 366 vs. 365.

A leap year is a calendar year that contains 366 days as compared to the 365 days contained by an ordinary calendar year. A year that is not a leap year is called a common year.

A leap year contains one additional day over the common year: the February 29th (the leap day). In a common year the month of February has only 28 days and February 29th does not exist.