English > unit of time: 1 sense > noun 1, time| Meaning | A unit for measuring time periods. |
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| Synonym | time unit |
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| Narrower | attosecond | one quintillionth (10^-18) of a second |
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| bell, ship's bell | (nautical) each of the eight half-hour units of nautical time signaled by strokes of a ship's bell |
| day, twenty-four hours, twenty-four hour period, 24-hour interval, solar day, mean solar day | Time for Earth to make a complete rotation on its axis |
| femtosecond | One quadrillionth (10^-15) of a second |
| half-hour, 30 minutes | A half of an hour |
| hour, hr, 60 minutes | A period of time equal to 1/24th of a day |
| mean time, mean solar time | (astronomy) time based on the motion of the mean sun (an imaginary sun moving uniformly along the celestial equator) |
| microsecond | One millionth (10^-6) of a second |
| millisecond, msec | One thousandth (10^-3) of a second |
| minute, min | A unit of time equal to 60 seconds or 1/60th of an hour |
| month | A time unit of approximately 30 days |
| nanosecond | One billionth (10^-9) of a second |
| night | The dark part of the diurnal cycle considered a time unit |
| picosecond | One trillionth (10^-12) of a second |
| quarter | A unit of time equal to 15 minutes or a quarter of an hour |
| quarter-hour, 15 minutes | A quarter of an hour |
| second, sec, s | 1/60 of a minute |
| 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 |
| terrestrial time, TT, terrestrial dynamical time, TDT, ephemeris time | (astronomy) a measure of time defined by Earth's orbital motion |
| Broader | measure, quantity, amount | How much there is or how many there are of something that you can quantify |
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| Spanish | unidad de tiempo |
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| Catalan | unitat de temps |
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