English word helio- comes from Proto-Indo-European *sol-, and later Proto-Hellenic *hāwélios (Sun.)

Detailed word origin of helio-

Dictionary entry	Language	Definition
*sol-	Proto-Indo-European (ine-pro)	whole
*hāwélios	Proto-Hellenic (grk-pro)	Sun.
ἥλιος	Ancient Greek (grc)
helio-	English (eng)	Concerning the sun.

Words with the same origin as helio-