diurnal

[ dahy-ur-nl ]
/ daɪˈɜr nl /

adjective

of or relating to a day or each day; daily.
of or belonging to the daytime (opposed to nocturnal).
Botany. showing a periodic alteration of condition with day and night, as certain flowers that open by day and close by night.
active by day, as certain birds and insects (opposed to nocturnal).

noun

Origin of diurnal

1400–50; late Middle English < Latin diurnālis, equivalent to diurn(us) daily + -ālis -al1

Related forms

Can be confused

diurnal nocturnal
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for diurnal

British Dictionary definitions for diurnal

diurnal

/ (daɪˈɜːnəl) /

adjective

happening during the day or daily
(of flowers) open during the day and closed at night
(of animals) active during the dayCompare nocturnal

noun

a service book containing all the canonical hours except matins

Derived Forms

diurnally, adverb

Word Origin for diurnal

C15: from Late Latin diurnālis, from Latin diurnus, from diēs day
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for diurnal

diurnal

[ dī-ûrnəl ]

adj.

Having a 24-hour period or cycle; daily.
Occurring or active during the daytime rather than at night.

Related forms

di•urnal•ly adv.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for diurnal

diurnal

[ dī-ûrnəl ]

  1. Occurring once in a 24-hour period; daily.
  2. Having a 24-hour cycle. The movement of stars and other celestial objects across the sky are diurnal.
Most active during the daytime. Many animals, including the apes, are diurnal.
Having leaves or flowers that open in daylight and close at night. The morning glory and crocus are diurnal. Compare nocturnal.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.