DIURNAL, a. [L., daily.] 1. Relating to a day; pertaining to the daytime; as diurnal heat; diurnal hours.2. Daily; happening every day; performed in a day; as a diurnal task.3. Performed in 24 hours; as the diurnal revolution of the earth.4. In medicine, an epithet of diseases whose exacerbations are in the day time; as a diurnal fever.DIURNAL, n. A day-book; a journal. [See Journal, which is mostly used.]
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