heliolˈogy noun

The science of the sun

heliomˈeter noun

An instrument for measuring angular distances, such as the sun's diameter

heliometˈric or heliometˈrical adjective

heˈliopause noun

(Gr pausis cessation) the boundary of the heliosphere (qv below)

heliophˈilous adjective

(Gr phileein to love) fond of the sun

heliophoˈbic adjective

(Gr phobos fear) fearing or shunning sunlight

heˈliophyte noun

(Gr phyton a plant) a plant that can live in full exposure to sunlight

heliosciophyte /hē-li-ō-sīˈō-fīt/ noun

(Gr skiā shadow) a plant that can live in shade but does better in the sun

heˈlioscope /-skōp/ noun

(Gr skopeein to look at) an apparatus for observing the sun without injury to the eye

helioscopic /-skopˈik/ adjective

heliōˈsis noun

1. (Gr hēliōsis) (over-)exposure to the sun
2. The spotting of leaves by raindrops, or by greenhouse glass flaws, etc acting as burning-glasses

heˈliosphere noun

(Gr sphaira sphere) the region around the sun (including the earth) that is filled with solar magnetic fields, in which the sun's heat is effective

heliospherˈic adjective

heˈliostat noun

(Gr statos fixed) an instrument on the principle of the coelostat by means of which a beam of sunlight is reflected in an invariable direction, for study of the sun or for signalling

heliotaxˈis noun

(Gr taxis arrangement) response of an organism to the stimulus of the sun's rays

heliotherˈapy noun

(Gr therapeiā healing) medical treatment by exposure to the sun's rays

heliotrope /hēˈli-ō-trōp or helˈi-ō-trōp/ noun

1. (Gr hēliotropion) any plant of the genus Heliotropium of the borage family, many species with fragrant flowers, esp the Peruvian heliotrope, with small fragrant lilac-blue flowers
2. The colour of its flowers
3. A kind of perfume imitating that of the flower
4. A bloodstone (mining)
5. A surveyor's heliograph

heliotropic /-tropˈik/ or heliotropˈical adjective

heliotropˈically adverb

heliotˈropin noun

Piperonal

heliotropism /-otˈrə-pizm/ or heliotˈropy noun

The tendency of stem and leaves to bend towards (positive heliotropism), and roots from (negative heliotropism), the light

heˈliotype noun

(Gr typos impression) a photograph by heliotypy

heliotypic /-tipˈik/ adjective

heˈliotypy /-tī-pi/ noun

A photomechanical process in which the gelatine relief is itself used to print from

Heliozōˈa plural noun

(Gr zōion an animal) sun-animalcules, an order of Protozoa, spherical with radiating processes of living matter

heliozōˈan adjective and noun

heliozōˈic adjective