• (a.) Relating to, or showing, geotropism.
Describes the response of plants toward the pull of gravity. ... (09 Oct 1997) ... 
Turning downward in response to a stimulus caused by the force of gravity.
Ge`o·trop'ic adjective [ See Geotropism .] (Biol.) Relating to, or showing, geotropism. 
Geotropic is a biological term describing plants whose roots grow downwards into the soil in response to gravity.
geotropic 1. A description of the response of plants toward the pull of gravity. 2. An organism that responds to the force of gravity with movement towards the center of the earth.