English

heliotherapy

From helio- + therapy.

Proto-Indo-European *sóh₂wl̥ ‘sun’

Proto-Hellenic *hāwélios ‘sun’

Ancient Greek ἥλιος ‘sun’

Ancient Greek θεράπων ‘attendant, aide’

Ancient Greek θεραπεύω ‘to serve, treat medically’

Ancient Greek θεραπεία ‘service, medical treatment’

New Latin therapīa ‘therapy’

Today it means

noun Any medical therapy by exposure to light.

Language periods are conventional ranges, not dates for this word.

Etymograph / heliotherapy