photoperiod

(redirected from photoperiodical)
Also found in: Medical.

pho·to·pe·ri·od

 (fō′tō-pîr′ē-əd)
n.
The daily duration of light and dark to which an organism is exposed, considered especially with regard to its effect on growth and development.

pho′to·pe′ri·od′ic (-ŏd′ĭk) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

photoperiod

(ˌfəʊtəʊˈpɪərɪəd)
n
(Botany) the period of daylight in every 24 hours, esp in relation to its effects on plants and animals
ˌphotoˌperiˈodic adj
ˌphotoˌperiˈodically adv
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

pho•to•pe•ri•od

(ˌfoʊ təˈpɪər i əd)

n.
the interval in a 24-hour period during which an organism is exposed to light.
[1915–20]
pho`to•pe`ri•od′ic (-ˈɒd ɪk) adj.
pho`to•pe`ri•od′i•cal•ly, adv.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.