quantity, amount, measure - how much there is of something that you can quantify

day, mean solar day, solar day, twenty-four hours - time for Earth to make a complete rotation on its axis; "two days later they left"; "they put on two performances every day"; "there are 30,000 passengers per day"

night - the dark part of the diurnal cycle considered a time unit; "three nights later he collapsed"

mean solar time, mean time - (astronomy) time based on the motion of the mean sun (an imaginary sun moving uniformly along the celestial equator)

ephemeris time, TDT, terrestrial dynamical time, terrestrial time, TT - (astronomy) a measure of time defined by Earth's orbital motion; terrestrial time is mean solar time corrected for the irregularities of the Earth's motions

month - a time unit of 30 days; "he was given a month to pay the bill"

sidereal day, day - the time for one complete rotation of the earth relative to a particular star, about 4 minutes shorter than a mean solar day

ship's bell, bell - (nautical) each of the eight half-hour units of nautical time signaled by strokes of a ship's bell; eight bells signals 4:00, 8:00, or 12:00 o'clock, either a.m. or p.m.

60 minutes, hour, hr - a period of time equal to 1/24th of a day; "the job will take more than an hour"

30 minutes, half-hour - a half of an hour

15 minutes, quarter-hour - a quarter of an hour

min, minute - a unit of time equal to 60 seconds or 1/60th of an hour; "he ran a 4 minute mile"

quarter - a unit of time equal to 15 minutes or a quarter of an hour; "it's a quarter til 4"; "a quarter after 4 o'clock"

s, sec, second - 1/60 of a minute; the basic unit of time adopted under the Systeme International d'Unites

millisecond, msec - one thousandth of a second

attosecond - one quintillionth of a second; one thousandth of a femtosecond

femtosecond - one quadrillionth of a second; one thousandth of a nanosecond

picosecond - one trillionth of a second; one thousandth of a nanosecond

nanosecond - one billionth of a second; one thousandth of a microsecond

microsecond - one millionth of a second; one thousandth of a millisecond