sidereal hour(n = noun.time) - 1/24 of a sidereal day;
is a kind of sidereal time, 60 minutes, hour, hr

by the hour, canonical hour, credit hour, early-morning hour, eleventh hour, happy hour, hour, hour angle, hour circle, hour hand, kilometers per hour, kilometres per hour, kilowatt hour, late-night hour, light hour, man hour, miles per hour, person hour, rush hour, semester hour, sidereal, sidereal day, sidereal month, sidereal time, sidereal year, twenty-four hour period, witching hour, zero hour