An hour is a unit of time — it's sixty minutes, 3,600 seconds, or the length it takes the long hand on your watch to move in a full circle.

If your math class lasts an hour, it might start at 9:30 and end at 10:30, one hour later. Hour also means "time of day." If your phone rings at two a.m., you could ask, "Why are you calling at such a late hour, Mom?" The word stems from the Old French hore, "one-twelfth of a day," with its roots in the Latin hora, "hour" or "season," and Greek hora, "the season."

Definitions of hour

n a period of time equal to 1/24th of a day

“the job will take more than an hour
60 minutes, hr
sidereal hour
1/24 of a sidereal day
man hour, person hour
a time unit used in industry for measuring work
Type of:
time unit, unit of time
a unit for measuring time periods

n distance measured by the time taken to cover it

“we live an hour from the airport”
Type of:
the property created by the space between two objects or points

n clock time

“the hour is getting late”
time of day
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high noon, midday, noon, noonday, noontide, twelve noon
the middle of the day
the hour at which a meal is habitually or customarily eaten
late-night hour
the latter part of night
12 o'clock at night; the middle of the night
small hours
the hours just after midnight
the time you go to bed
closing time
the regular time of day when an establishment closes to the public
aurora, break of day, break of the day, cockcrow, dawn, dawning, daybreak, dayspring, first light, morning, sunrise, sunup
the first light of day
early-morning hour
an hour early in the morning
sundown, sunset
the time in the evening at which the sun begins to fall below the horizon
crepuscle, crepuscule, dusk, evenfall, fall, gloam, gloaming, nightfall, twilight
the time of day immediately following sunset
a canonical hour that is the ninth hour of the day counting from sunrise
happy hour
the time of day when a bar sells alcoholic drinks at a reduced price
rush hour
the times at the beginning and end of the working day when many people are traveling to or from work
zero hour
the time set for the start of an action or operation
canonical hour
(Roman Catholic Church) one of seven specified times for prayer
breakfast time
the customary or habitual hour for eating breakfast
lunch period, lunchtime
the customary or habitual hour for eating lunch
dinnertime, suppertime
the customary or habitual hour for the evening meal
a prescribed bedtime
a shortening of nightfall
matins, morning prayer
the first canonical hour; at daybreak
the second canonical hour; about 6 a.m.
terce, tierce
the third canonical hour; about 9 a.m.
the fourth of the seven canonical hours; about noon
the fifth of the seven canonical hours; about 3 p.m.
evensong, vespers
the sixth of the seven canonical hours of the divine office; early evening; now often made a public service on Sundays
complin, compline
last of the seven canonical hours just before retiring
Type of:
clock time, time
a reading of a point in time as given by a clock

n a special and memorable period

“it was their finest hour
Type of:
period, period of time, time period
an amount of time

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