This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. The turning or bending movement of an organism or a part toward or away from an external stimulus, such as light, heat, or gravity.

n. the turning of an organism in response to a stimulus, either towards or away from the stimulus

n. viral tropism, or which type of tissue supports a certain virus

n. Modification of the direction of growth, caused by some external influence, such as light; -- sometimes used for motion of an organism toward or away from an external stimulus, more properly called taxis.

n. In biology, growth, bending, orientation, or locomotion of organisms, or of parts of organisms, in relation to external agents.

n. In a stricter use, the growing or bending of organisms, or of parts of organisms, in relation to external agents.

n. an involuntary orienting response; positive or negative reaction to a stimulus source

"Such a turning in response to a stimulus is called a tropism (troh'pizm; "turning" G)."

taxis   

reaction    response   

heliotropism    meteortropism    trophotropism    neurotropism    ergotropism    thermotropism    geotropism    phototropism   

gravitropism    skototropism    thermotropism    geotropism    thigmotropism    hydrotropism    phototropism    chemotropism   

behindthe    capsid    bohea    infantilism    accomodations    infectivity    self-talk    pervasiveness    unattractiveness    becomingness