phototropism
|pho-to-trop-ism|
🇺🇸
/ˌfoʊtəˈtroʊpɪzəm/
🇬🇧
/ˌfəʊtəˈtrəʊpɪzəm/
turn (or grow) toward light
Etymology
'phototropism' originates from Greek, specifically the combining form 'photo-' from 'phōtós' meaning 'light' and 'tropos' meaning 'turn', plus the suffix '-ism' used to form nouns describing actions or conditions.
'phototropism' was coined in modern scientific/biological English (and New Latin usage) in the 19th century by combining the Greek elements 'phōtós' and 'trópos' to name the observed light-directed turning of organisms; it did not evolve from a medieval English word but from scholarly coinage.
Initially, it meant 'turning in response to light' in biological observation, and over time it has remained specialized to describe growth or movement toward or away from light in organisms.
Meanings by Part of Speech
Noun 1
a biological phenomenon in which an organism, especially a plant, grows or moves in response to light, typically bending toward (positive phototropism) or away from (negative phototropism) a light source.
Young seedlings show phototropism by bending toward a nearby light source.
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Noun 2
in a broader sense, any movement or directional change of organisms (or parts of organisms) caused specifically by the direction or intensity of light.
Phototropism can affect the orientation of leaves, stems, and flowers in many species.
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Last updated: 2025/08/27 16:13