What term describes the movement of an organism in response to a touch stimulus?

Thigmotropism refers to the directional growth or movement of an organism in response to touch or physical contact with an object. This term is commonly used in botany to describe how certain plants, such as climbing vines, wrap around support structures when they encounter them. The process involves mechanoreceptors that detect touch stimuli, prompting the plant to grow towards or around the object.

In contrast, hydrotropism is the growth response of plants to moisture gradients, chemotropism relates to movement in response to chemical signals, and phototropism is the growth towards light sources. Each of these terms describes different stimuli and responses, while thigmotropism specifically pertains to touch. Thus, thigmotropism is the correct answer as it accurately describes the movement of an organism in direct response to a touch stimulus.