Common year
A common year is a calendar year with 365 days.  It is a year that is not a leap year. This means a common year has 52 weeks and one day.  So if a certain year started on a Monday, the following year will start on a Tuesday.  Stated differently, a common year always begins and ends on the same day of the week. (For example, in 2023, both January 1 and December 31 falls on a Sunday.)