The business to be done by a body (such as a legislature) on a particular day; an agenda. / The most significant aspect of something; what is necessary or appropriate.

(set phrase) At some unspecified time in the future. / At some unspecified time in the past. / Used other than figuratively or idiomatically: see one, day.

formerly, a day of the week on which a household’s laundry would be washed and dried; traditionally a Monday in Britain

(chiefly Britain and Ireland) Shrove Tuesday; in some traditions the day for pancake races for charity.

(Britain, Ireland) A day on which a registered charity raises money, usually by selling small lapel flags. / (software) A day designated for changing to an incompatible system.

Victory in Europe day; the anniversary of the end of the Second World War in Europe, 8 May 1945.

Lasting throughout the whole day. / Available throughout the whole day.

(military) A day for manoeuvres and tactical exercises in "the field". / A school day for athletic events; a sports day. / A day of class taken away from school for a field trip.

(historical) 6 June 1944, the date when the Allies invaded western Europe in World War II.

(figuratively) The date of any major event planned for the future.