昼 晝 zhou4
daytime

strokes 11
radical
日
日
strokes after radical 7
白昼 白晝 bai2 zhou4
daytime

俾夜作昼 俾夜作晝 bi3 ye4 zuo4 zhou4
lit. to make night as day (idiom); fig. to burn the midnight oil; work especially hard

俾昼作夜 俾晝作夜 bi3 zhou4 zuo4 ye4
to make day as night (idiom, from Book of Songs); fig. to prolong one's pleasure regardless of the hour

卜昼卜夜 卜晝卜夜 bu3 zhou4 bu3 ye4
day and night (to toil, to abandon oneself to pleasure etc)

不分昼夜 不分晝夜 bu4 fen1 zhou4 ye4
day and night; round-the-clock

俨如白昼 儼如白晝 yan3 ru2 bai2 zhou4
as bright as daylight (idiom)

夜行昼伏 夜行晝伏 ye4 xing2 zhou4 fu2
to travel at night and lie low by day (idiom)

宰予昼寝 宰予晝寢 zai3 yu3 zhou4 qin3
Zai Yu sleeps by day (idiom); refers to story in Analects of Confucius remonstrating bitterly with his student for sleeping during lectures

昼短夜长 晝短夜長 zhou4 duan3 ye4 chang2
the winter days are short and the nights long (idiom)

昼伏夜出 晝伏夜出 zhou4 fu2 ye4 chu1
nocturnal; to hide by day and come out at night

昼夜 晝夜 zhou4 ye4
day and night; period of 24 hours; continuously, without stop

昼夜节律 晝夜節律 zhou4 ye4 jie2 lv4
circadian rhythm

昼夜平分点 晝夜平分點 zhou4 ye4 ping2 fen1 dian3
the equinox