282. Motion

See also 399. TRAVEL .

apheliotropism

the tendency of some plants to grow in a direction away from the sun.

apogeotropism

the tendency of some plants to grow away from the earth and the pull of gravity. —apogeotropic , adj.

bradykinesia, bradykinesis

slowness of movement. —bradykinetic , adj.

chemotaxis

the property of some plants and animals of moving toward or away from certain chemicals.

chemotropism

growth or motion in response to a chemical stimulus. —chemotropic , adj.

diatropism

the capacity or tendency of some plants to adopt a position transverse to the line of force of an external stimulus. — diatropic , adj.

dromophobia

kinetophobia.

galvanotropism

growth or movement of an organism in response to an electric current. —galvanotropic , adj.

geotaxis

the movement of an organism in response to the force of gravity.

kinematics

the study of the motion of bodies considered independently of external forces. Also called phoronomy . —kinematic , adj.

kinesomania

a mania for movement.

kinetics

the branch of physics that studies the motion of masses in relation to the forces acting on them.

kinetophobia

an abnormal fear or dislike of motion. Also called dromophobia .

phoronomy

kinematics.

photokinesis

movement of bodies, organisms, etc., in response to the stimulus of light. —photokinetic , adj.

phototaxis, phototaxy

the movement of an organism away from or toward a source of light. —phototactic , adj.

phototropism

motion in a particular direction under the stimulus of light, as exhibited by certain plants, organisms, etc. —phototropic , adj.

rheotaxis

the tendency of certain living things to move in response to the mechanical stimulus of a current of water.

stereotaxis

orientation or movement of an organism in response to the stimulus of a solid object. Cf. stereotropism. —stereotactic , adj.

stereotropism

growth or movement determined by contact with a solid. Also called thigmotropism . Cf. stereotaxis. —stereotropic , adj.

tachophobia

an abnormal fear of speed.

thigmotropism

stereotropism. —thigmotropic , adj.

trochilics

Rare. the science of rotary motion. —trochilic , adj.

trophotropism

the movement of cells in relation to food or nutritive matter. —trophotropic, adj.

tropism

the tendency of a plant, animal, or part to move or turn in response to an external stimulus, as sunlight or temperature. —tropistic , adj.