[ foh-tot-n-uh s ]
/ foʊˈtɒt n əs /
the normal condition of sensitiveness to light in organisms or their organs.
the irritability exhibited by cytoplasm when exposed to light of a certain intensity.
Related formspho·to·ton·ic [foh-tuh-ton-ik] /ˌfoʊ təˈtɒn ɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for phototonus
/ (fəʊˈtɒtənəs) /
the condition of plants that enables them to respond to the stimulus of light
Derived Formsphototonic (ˌfəʊtəʊˈtɒnɪk), adjective
Word Origin for phototonus
C19: from photo- + Greek tonos tone
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 phototonus
[ fō-tŏt′n-əs ]
The state of being sensitive to or irritated by light.
Related formspho′to•ton′ic (fō′tə-tŏn′ĭk) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.