heliotropism
definition
the growth or movement of a plant toward sunlight
example
The concept of heliotropism explains how sunflowers turn their heads to follow the sun throughout the day.
synonyms
phototropismlight-seekingsolar movement
word origin — The term 'heliotropism' comes from the Greek words 'helios' meaning 'sun' and 'tropos' meaning 'turn' or 'turning'.