week calendar

calendar [...] based on an unbounded series of contiguous calendar weeks [...] that uses the time scale unit [...] of calendar week as its basic unit to represent a calendar year [...], according to the rule that the first calendar week of a calendar year is the week including the first Thursday of that year, and that the last one is the week immediately preceding the first calendar week of the next calendar year Note 1 to entry: This rule is based on the principle that a week belongs to the calendar year to which the majority of its calendar days [...] belong. Note 2 to entry: In the week calendar, calendar days of the first and last calendar week of a calendar year may belong to the previous and the next calendar year respectively in the Gregorian calendar [...].