Main Entry: ¹di·ur·nal

Pronunciation: \dī-ˈər-n^əl\

Function: adjective

Etymology: Middle English, from Latin diurnalis — more at journal

Date: 14th century

1 a : recurring every day <diurnal tasks> b : having a daily cycle <diurnal tides>
2 a : of, relating to, or occurring in the daytime <the city's diurnal noises> b : active chiefly in the daytime <diurnal animals> c : opening during the day and closing at night <diurnal flowers>

— di·ur·nal·ly \-n^əl-ē\ adverb