diurnal

diurnal [ DAHY-ur-nl ]
[ noun, adjective ]

MEANING :
1. (adj.) daily or pertaining to a day or 24 hour period
2. (adj.) occurring during or belonging to the day time
3. (n.) a book containing the prayers for the daily hours of prayer
2. (n.) a daily newspaper

USAGE EXAMPLE 1 :
The doctor advised him to change his job as working the night shift had caused abnormal diurnal variations in his blood pressure.

USAGE EXAMPLE 2 :
They are also diurnal, and are active through most of the day – unlike other armadillo species, which are mostly nocturnal.