from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The growth of a living organism in response to gravity, as the downward growth of plant roots.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The movement of a plant in response to gravity (either downwards or upwards)
from the GNU version of the Collaborative International Dictionary of English
- n. A disposition to turn or incline towards the earth; the influence of gravity in determining the direction of growth of an organ.
from The Century Dictionary and Cyclopedia
- n. In botany, growth downward, as shown in the roots of plants and sometimes in stems and rootstocks; the power or tendency to grow toward the earth.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an orienting response to gravity
Once plant life invaded the land it was subject to the action of gravity, and geotropism ( "earth-turning" G), involving an automatic and adaptive response to gravity, was developed.
But atavistic, or vestigial, geotropism in Genesistrine -- or a million larvae start crawling, and a million little frogs start hopping -- knowing no more what it's all about than we do when we crawl to work in the morning and hop away at night.
They give the quintessence of laboratory experiments as to what are the effects of different energies such as light (heliotropism), electricity (galvanotropism), gravity (geotropism), etc., in their reaction and influence upon the movements and actions of living organisms.
Thus I am now observing something about geotropism, and I had no idea a few weeks ago that this would have been necessary.