[di.ur.nal] adj [ME, fr. L diurnalis--more at journal] (14c) 1 a: recurring every day "~ tasks" b: having a daily cycle "~ tides"
2. a: of, relating to, or occurring in the daytime "the city's ~ noises" b: active chiefly in the daytime "~ animals" c: opening during the day and closing at night "~ flowers" -- di.ur.nal.ly adv
[2]diurnal n (1600) 1 archaic: diary, daybook
2: journal 2a