# HyperDic: unit_of_time

 NOUN time unit of time, time unit a unit for measuring time periods
Meaning Synonym A unit for measuring time periods. time unit attosecond one quintillionth (10^-18) of a second 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 measure, quantity, amount How much there is or how many there are of something that you can quantify unidad de tiempo unitat de temps