the interval of light between two successive nights; the time between sunrise and sunset.
Since there was no artificial illumination, all activities had to be carried on during the day.
the light of day; daylight.
The owl sleeps by day and feeds by night.
Astronomy.
Also called mean solar day. a division of time equal to 24 hours and representing the average length of the period during which the earth makes one rotation on its axis.
Also called solar day. a division of time equal to the time elapsed between two consecutive returns of the same terrestrial meridian to the sun.
Also called civil day. a division of time equal to 24 hours but reckoned from one midnight to the next.
an analogous division of time for a planet other than the earth.
the Martian day.
the portion of a day allotted to work.
an eight-hour day.
a day on which something occurs.
the day we met.
(often initial capital letter) a day assigned to a particular purpose or observance.
New Year's Day.
a time considered as propitious or opportune.
His day will come.
a day of contest or the contest itself.
to win the day.
Often a particular time or period.
the present day; in days of old.
Usually period of life or activity.
His days are numbered.
period of existence, power, or influence.
in the day of the dinosaurs.
Architecture. light.
day in, day out, every day without fail; regularly: Also day in and day out
They endured the noise and dirt of the city day in, day out.
day and night. night.
call it a day, to stop one's activity for the day or for the present; quit temporarily.
After rewriting the paper, she decided to call it a day.
Benjamin Henry, 1810–89, U.S. newspaper publisher.
Clarence (Shepard) 1874–1935, U.S. author.
Dorothy, 1897–1980, U.S. Roman Catholic social activist, journalist, and publisher.
Also Daye Stephen, 1594?–1668, U.S. colonist, born in England: considered the first printer in the Colonies.
Also called: civil day. the period of time, the calendar day, of 24 hours' duration reckoned from one midnight to the next
the period of light between sunrise and sunset, as distinguished from the night
( as modifier )
the day shift
the part of a day occupied with regular activity, esp work
he took a day off
(sometimes plural) a period or point in time
he was a good singer in his day
in days gone by
any day now
the period of time, the sidereal day, during which the earth makes one complete revolution on its axis relative to a particular star. The mean sidereal day lasts 23 hours 56 minutes 4.1 seconds of the mean solar day
the period of time, the solar day, during which the earth makes one complete revolution on its axis relative to the sun. The mean solar day is the average length of the apparent solar day and is some four minutes (3 minutes 56.5 seconds of sidereal time) longer than the sidereal day
the period of time taken by a specified planet to make one complete rotation on its axis
the Martian day
(often capital) a day designated for a special observance, esp a holiday
Christmas Day
part of one's normal activity; no trouble
in the final reckoning
the Sabbath; Sunday
to pass the end of one's life
one's luck will come
nowadays
it's too early to tell how things will turn out
very late (in a particular situation)
too late
I look forward to that
that is most unlikely to happen
a time of success, recognition, power, etc
his day will soon come
a struggle or issue at hand
the day is lost
the ground surface over a mine
( as modifier )
the day level
without thinking of the future
to stop work or other activity
without respite; relentlessly
gradually or progressively; daily
he weakened day by day
every day and all day long
from the very beginning
at some future time
(modifier) of, relating to, or occurring in the day
the day shift
First recorded before 950; Middle English; Old English dæg; cognate with German Tag
A day is a 24-hour period, or the length of time it takes the Earth to rotate fully on its axis. There are 365 days in a year, and 31 days in the month of January. Most work weeks last five days, and an ordinary weekend gives you two days of freedom before you go back to work or school. Day can also mean the opposite of night, or the time when the sun is up and you're awake. If your grandpa starts his stories with, "Back in my day..." he means an era or a period of time in the past. The Old English root, dæg, means both "day" and "lifetime."
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
That’s the view of Fundstrat managing partner and head of research Tom Lee, who has just added software to his top-sector picks in our call of the day.
From MarketWatch • May 1, 2026
Warren Buffett didn’t need the ego boost, but the fact that Berkshire Hathaway hit its all-time peak the day before his surprise retirement announcement at last year’s annual meeting is telling.
From The Wall Street Journal • May 1, 2026
It must be postmarked on or before election day, June 2.
From Los Angeles Times • May 1, 2026
That dry powder is a drag on returns right now, but a crisis that gives Abel an opportunity to deploy it will come as surely as night follows day.
From The Wall Street Journal • May 1, 2026
“Nice day for the party, Miss,” he said, trying to peer past the flowers as though coffee and cake might already be set out.
From "The Hiding Place" by Corrie ten Boom
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
