Theias

Theias is a term that may appear in texts as a plural form or variant spelling related to the more common name Theia. It is not widely used as a standalone term in established references, where Theia (singular) is standard for the primary topics it can denote.

In Greek mythology, Theia is a Titaness associated with sight and the bright ether of the sky. She is commonly described as a daughter of Gaia (Earth) and Uranus (Sky) and, in Hesiod’s accounts, the mother of Helios (the Sun), Selene (the Moon), and Eos (the Dawn) with Hyperion. When Theia is referred to in plural form as Theias, it may indicate multiple figures named Theia or simply represent an inflected usage in English, but such usage is uncommon and not part of canonical mythological scholarship.

In astronomy and planetary science, Theia (with a capital T) denotes the hypothetical protoplanet proposed to have collided with the early Earth to form the Moon, a central element of the giant-impact hypothesis. Theias as a plural or variant spelling is rarely used in this scientific context; Theia remains the standard designation.

Other uses of Theias are not widely established in major reference works. When encountered, Theias most often signals either a pluralization of Theia or a misspelling/misreading of Theia. Context typically clarifies whether the reference concerns the mythological Titaness, the hypothetical protoplanet, or a different, less common usage.