day and night; period of 24 hours; continuously, without stop

daytime

polar day

diurnality; diurnal

day and night; round-the-clock

lit. to make night as day (idiom); fig. to burn the midnight oil; work especially hard

to make day as night (idiom, from Book of Songs); fig. to prolong one's pleasure regardless of the hour

day and night (to toil, to abandon oneself to pleasure etc)

to travel at night and lie low by day (idiom)

nocturnal; to hide by day and come out at night

circadian rhythm

the equinox