heliotrope n.

*sāwel-, Proto-Indo-European root meaning "the sun." According to Watkins, the *-el- in it originally was a suffix, and there was an alternative form *s(u)wen-, with suffix *-en-, hence the two forms represented by Latin sol, English sun.

It forms all or part of: anthelion; aphelion; girasole; heliacal; helio-; heliotrope; helium; insolate; insolation; parasol; parhelion; perihelion; Sol; solar; solarium; solstice; south; southern; sun; Sunday.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit suryah, Avestan hvar "sun, light, heavens;" Greek hēlios; Latin sol "the sun, sunlight;" Lithuanian saulė, Old Church Slavonic slunice; Gothic sauil, Old English sol "sun;" Old English swegl "sky, heavens, the sun;" Welsh haul, Old Cornish heuul, Breton heol "sun;" Old Irish suil "eye;" Avestan xueng "sun;" Old Irish fur-sunnud "lighting up;" Old English sunne German Sonne, Gothic sunno "the sun."

Proto-Indo-European root meaning "to turn."

It forms all or part of: apotropaic; atropine; Atropos; contrive; entropy; heliotrope; isotropic; psychotropic; retrieve; trope; -trope; trophy; tropic; tropical; tropism; troposphere; troubadour; zoetrope.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit trapate "is ashamed, confused," properly "turns away in shame;" Greek trepein "to turn," tropos "a turn, direction, course," trope "a turning;" Latin trepit "he turns."

1854, from heliotrope + -ism.