diurnal
UK: daɪˈɜː.nəl | US: daɪˈɜːr.nəl
adj. relating to or occurring during the daytime
adj. (biology) active during the day (opposite of nocturnal)
adj. (astronomy) completing a cycle within one day
The word "diurnal" originates from Latin diurnalis, derived from dies (day). The morpheme di- preserves the core meaning of "day," while -urnal (via Latin -urnalis) signifies connection or repetition. Over time, it evolved in English to describe daily cycles, daytime activity, or astronomical phenomena. The logical progression reflects a shift from general "daily" (Latin) to specialized scientific uses (biology/astronomy).
Diurnal animals like squirrels are most active at dawn.
The diurnal temperature variation was recorded by meteorologists.
Some flowers exhibit diurnal rhythms, opening only in sunlight.
In astronomy, a diurnal motion refers to Earth’s daily rotation.
His diurnal habits contrasted sharply with his nocturnal roommate.