Tropism
Tropism (from the Greek trepô, "turn") means the movement towards a stimulus or the inclination towards something. This means:
- Orientation of a plant organ towards the stimulus or away from it, see plant movement #Nastia and tropisms
- Tropism (zoology) , orientation of a sessile animal towards or away from the stimulus
- Organotropism , a special affinity of drugs, hormones or pathogens to special organs or tissues
- Tropism (virology) , the species or organ specificity and the ability of a virus to penetrate a particular cell and multiply there