The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The movement or orientation of an organism in response to two stimuli, especially lights, by means of different sense organs.
- troˌpo·tacˈtic adjective
- troˌpo·tacˈti·cal·ly adverb