calendar day noun2 •A timespan of exactly 24 hours, measured from one midnight to the next.Travel insurance is available at the special price of pounds 4 for one calendar day, pounds 10 up to 36 hours. — 1997 •A day having a conventional designation on a recognized calendar, such as a numerical identification within a named month.'[T]is wonderful where or when we ever got anything of this which we call wisdom, poetry, virtue. We never got it on any dated calendar day. — 1844 formscalendar days
