Definition of heliotropism in US English:

heliotropism

noun

Botany
  • 1The directional growth of a plant in response to sunlight.

    Compare with phototropism
    • ‘All legume plants do this, so be sure to watch your peas and beans for signs of heliotropism.’
    • ‘The adaptive significance of solar tracking in snow buttercups is mediated through the impact of flower heliotropism on paternal and maternal floral environments.’
    • ‘The heliotropism itself is an adaptation for survival, the plant maximizing sunlight.’
    1. 1.1Zoology The tendency of an animal to move toward light.

Pronunciation

heliotropism

/ˌhiliəˈtroʊpɪzəm//ˌhēlēəˈtrōpizəm/