Helios was the sun,
of course, or rather its god. Originally he was also known as
Hyperion or
Phoebus, but these became dissociated from him. His name means what he is, 'sun' (helios), in turn perhaps from hele, 'bright', 'hot' (see Helen). His
Roman name is Sol, which is actually a variant of Helios since 'h' in Greek words often corresponds to 's' in their Latin counterparts (for example Greek hepta, 'seven' and Latin septem, Greek hyle, 'wood' and Latin silvd).