昼 (w)

(zhòu) daytime

昼伏夜出 (w)

(zhòufúyèchū) nocturnal; to hide by day and come out at night

昼夜 (w)

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

昼夜平分点 (w)

(zhòuyèpíngfēndiǎn) the equinox

昼短夜长 (w)

(zhòuduǎnyècháng) the winter days are short and the nights long (idiom)