a combining form meaning “sun,” used in the formation of compound words: heliolatry.
Also especially before a vowel, heli-.
Origin of helio-
< Greek, combining form of hḗlios sun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
before a vowel heli-
indicating the sunheliocentric; heliolithic
Word Origin for helio-
from Greek, from hēlios sun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
word-forming element meaning "sun," from Greek helio-, comb. form of helios "sun" (see sol).
Online Etymology Dictionary, © 2010 Douglas Harper