di·ur·nal 
(dī-ûrnəl)
(dī-ûrnəl)adj.
1. Relating to or occurring in a 24-hour period; daily.
2. Occurring or active during the daytime rather than at night: diurnal animals.
3. Botany Opening during daylight hours and closing at night.
n.
1. A book containing all the offices for the daily canonical hours of prayer except matins.
2. Archaic
a. A diary or journal.
b. A daily newspaper.
[Middle English, from Late Latin diurnālis, from Latin diurnus, from diēs, day; see dyeu- in the Appendix of Indo-European roots.]
di·urnal·ly adv.