diurnal
Concise Oxford English Dictionary © 2008 Oxford University Press:
diurnal /dʌɪˈəːn(ə)l/
▶adjective
- 1 of or during the daytime.
- 2 daily; of each day: diurnal rhythms.
– derivatives
diurnally adverb.
diurnally adverb.
– origin ME: from late L. diurnalis, from L. diurnus ‘daily’, from dies ‘day’.
'diurnal' also found in these Oxford entries:

