day

day and night;  I work at night and sleep during the day.

The day was cool and snappy for August, and the Rise all green with a lavish nature. Now we plunged into a deep shade with the boughs lacing each other overhead, and crossed dainty, rustic bridges over the cold trout-streams,[…].

1897 December (indicated as 1898), Winston Churchill, chapter VIII, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd., →OCLC:

The time when the Sun is above the horizon and it lights the sky.

A period of time equal or almost equal to a full day-night cycle.

The time taken for the Sun to seem to be in the same place in the sky twice; a solar day.

The time taken for the Earth to make a full rotation about its axis with respect to the fixed stars; a sidereal day or stellar day.

I've been here for two days and a bit.

Your 8am forecast: The high for the day will be 30 and the low, before dawn, will be 10.

(informal or meteorology) A 24-hour period beginning at 6am or sunrise.

The day begins at midnight.

Monday is the first day of the week in many countries of the world.

A period of time between two set times which mark the beginning and the end of day in a calendar, such as from midnight to the following midnight or (Judaism) from nightfall to the following nightfall.

A day on Mars is slightly over 24 hours.

(astronomy) The rotational period of a planet.

I worked two days last week.

“[…]if you call my duds a ‘livery’ again there'll be trouble. It's bad enough to go around togged out like a life saver on a drill day, but I can stand that 'cause I'm paid for it. What I won't stand is to have them togs called a livery.[…]”

1913, Joseph C[rosby] Lincoln, chapter VII, in Mr. Pratt’s Patients, New York, N.Y., London: D[aniel] Appleton and Company, →OCLC:

The part of a day period which one spends at one’s job, school, etc.

Christmas Day

Remembrance Day

An observance lasting for a day, such as an annual holiday.

every dog has its day; in that day; back in the day; in those days

This new-comer was a man who in any company would have seemed striking.[…]Indeed, all his features were in large mold, like the man himself, as though he had come from a day when skin garments made the proper garb of men.

1910, Emerson Hough, chapter I, in The Purchase Price: Or The Cause of Compromise, Indianapolis, Ind.: The Bobbs-Merrill Company, →OCLC:

If they had no more food than they had had in Jones's day, at least they did not have less.

1943 November – 1944 February (date written; published 1945 August 17), George Orwell [pseudonym; Eric Arthur Blair], Animal Farm […], London: Secker & Warburg, published May 1962, →OCLC:

In his senior year, he had run across an old '66 Chevy Super Sport headed for the junkyard, bought it for a song, and overhauled it with his dad's help, turning it into the big red muscle car it was back in its day.

2011, Kat Martin, A Song for My Mother^([200]), Vanguard Press, →ISBN:

A specified time or period; time, considered with reference to the existence or prominence of a person or thing; age; time; era.

The day belonged to the Allies.

A period of contention of a day or less.

days (plural)
daie (alternative)
daye (alternative)

any day of the week and twice on Sundays

even a stopped clock is right twice a day

every day of the week and twice on Sundays

Fundamentalist Church of Jesus Christ of Latter-day Saints

sufficient unto the day is the evil thereof

Sranan Tongo: dei

يَوْم

period from midnight to the following midnight

يَوْم

part of a day period which one spends at one's job, school, etc.

Etymology tree
Middle English day
English day
Inherited from Middle English day, from Old English dæġ (“day”), from Proto-West Germanic *dag, from Proto-Germanic *dagaz (“day”); see there for more.
Cognate with Saterland Frisian Dai (“day”), West Frisian dei (“day”), Dutch dag (“day”), German Low German Dag (“day”), Alemannic German Däi (“day”), German Tag (“day”), Swedish, Norwegian and Danish dag (“day”), Icelandic dagur (“day”), Gothic 𐌳𐌰𐌲𐍃 (dags, “day”). Possible cognates beyond Germanic relatives include Albanian djeg (“to burn”), Lithuanian degti (“to burn”), Tocharian A tsäk-, Russian жечь (žečʹ, “to burn”) from *degti, Sanskrit दाह (dāhá, “heat”), दहति (dáhati, “to burn”), Latin foveō (“to warm, keep warm, incubate”).
Latin diēs, Russian день (denʹ), Lithuanian dienà are false cognates; they all derive from Proto-Indo-European *dyew- (“to shine”).


day

I nighted and dayed in Damascus town[.]

1885, Richard F. Burton, chapter XXIII, in The Book of the Thousand Nights and a Night, volume I, The Burton Club, page 233:

(rare, intransitive) To spend a day (in a place).

en-verb

day (third-person singular simple present days, present participle daying, simple past and past participle dayed)

days (present singular third-person)
daying (participle present)
dayed (participle past)
dayed (past)
daie (alternative)
daye (alternative)

Sunday · Monday · Tuesday · Wednesday · Thursday · Friday · Saturday [edit]