Growth or movement of a sessile organism toward or away from a source of light.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "phototropism" in a sentence
"Maybe there's some phototropism in there as well they seem to be moving to the shadow at the top?"
"Make sure you look at the movies for morning glories twining, and corn seedling phototropism."
"Thus it was that the interpretations of J. Loeb (Die Tropismen, 1913) on the basis of experiments done with lower animals, estab - lished the neologist ideas of “phototropism” (orien - tation or displacement reaction in the direction of light), and of “thermotropism” (reaction directed to - wards a source of heat), to explain animal and perhaps also human behavior."