Definition
Calendar
A calendar organises dates into days, weeks, months, and years.
What it means
A calendar grid helps you locate a date and count forward or backward through days and weeks. Rows usually show weeks and columns show weekdays. Months are not all the same length, so longer jumps must follow the calendar instead of treating every month as an equal number of days.
Remember it
Move one date for one day, and follow the month when the row ends.
Example
Suppose 15 August is a Friday. Seven days later is 22 August, also a Friday, because one week is seven days. Counting three more days gives Monday, 25 August.
Watch for
A month is not a fixed number of days: in the Gregorian calendar, months have 28, 29, 30, or 31 days.
Common mix-up
Do not count the starting date as one day later; the next date is one day later.
Exact meaning
A calendar is a system for naming and arranging dates, commonly shown as days grouped into weeks, months, and years. Calendar calculations follow the actual lengths of months and the leap-year rules of the chosen calendar.