sentences: hours hr are a metric unit used for measuring time generally used for values between 025 and 72
docs: term is unit_of_time. time_unit is measure. hour is clock_time. unit_of_time is unit_of_measure. one_unit_of_time is minute. minute is time_unit. hours is units_of_time. mean_time is time_unit. one_unit_of_time is hour. hour is time_unit.