Main Entry: di·ur·nal

Pronunciation: \dī-ˈərn-^əl\

Function: adjective

1 : having a daily cycle <diurnal rhythms>
2 a : of, relating to, or occurring in the daytime <diurnal activity> b : chiefly active during the daytime <diurnal mosquitoes>

—di·ur·nal·ly \-^əl-ē\ adverb