heliotropism

noun

he·​li·​ot·​ro·​pism ˌhē-lē-ˈä-trə-ˌpi-zəm 

: phototropism in which sunlight is the orienting stimulus

heliotropic

ˌhē-lē-ə-ˈtrō-pik  -ˈträ- 

adjective

Word History

Etymology

borrowed from French héliotropisme, from hélio- helio- + -tropisme -tropism, after héliotrope -tropism

Note: The term was probably introduced by the Swiss naturalist Jean Senebier (1742-1809) in Physiologie végétale, tome 3 (Geneva, 1800?), p. 182.

First Known Use

circa 1854, in the meaning defined above

Kids Definition

heliotropism

noun

he·​li·​ot·​ro·​pism ˌhē-lē-ˈä-trə-ˌpiz-əm 

: a turning or curving (as of a sunflower head) toward the sunlight

Medical Definition

heliotropism

noun

he·​li·​ot·​ro·​pism ˌhē-lē-ˈä-trə-ˌpiz-əm 

: phototropism in which sunlight is the orienting stimulus

heliotropic

-lē-ə-ˈtrōp-ik  -ˈträp- 

adjective