(noun, adjective)


1. of or belonging to or active during the day

- diurnal animals are active during the day

- diurnal flowers are open during the day and closed at night

- diurnal and nocturnal offices

2. having a daily cycle or occurring every day

- diurnal rotation of the heavens

Similar word(s): periodic, periodical

Sentences with diurnal as an adjective:

- Most birds are diurnal.


1. A flower that opens only in the day.

2. (Catholicism) A book containing canonical offices performed during the day, hence not matins.

3. (archaic) A diary or journal.

4. (archaic) A daily news publication.