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

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

(idiomatic, abstractly) Healthy eating and living using traditional temperate-zone fresh foods.

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

(astronomy) one day of solar time, the time between successive noons; the time in which a planet such as Earth apparently rotates once around its axis, relative to the sun (on Earth about 24 hours as an average - the length of solar day is not constant throughout the year)

Used other than figuratively or idiomatically: see market, day. / The day of the week in which a market is held in some particular location.

(Canada) A holiday, originally to give thanks to God for the harvest, celebrated annually on the second Monday of October.

An extra day intercalated into a year, especially the day intercalated into the Julian calendar every fourth year and into the Gregorian calendar every fourth year excepting centuries not divisible by 400, usually reckoned as February 29th.

(Philippines) the day before yesterday.

An annual celebration commemorating the anniversary of a nation's assumption of independent statehood.