n.
Growth or movement of a sessile organism toward or away from a source of light.
phototropic pho'to·tro'pic (fō'tə-trō'pĭk, -trŏp'ĭk) adj.
phototropically pho'to·tro'pi·cal·ly adv.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.