Theia

//ˈθiːə// name

name ·Rare ·Advanced level

Definitions

Proper Noun
  1. 1
    A Titan, the sister-wife of Hyperion. Greek
  2. 2
    An Oceanid nymph (daughter of Oceanus and Tethys), the mother of the Cercopes by Oceanus. Greek
  3. 3
    A hypothesised Mars-sized planet of the early solar system thought to have collided with the Earth to produce the Moon.

    "According to the reigning hypothesis, about 4.5 billion years ago, shortly after Earth had accreted down into a sphere from its little slub of circumsolar material, another newborn planet, still shaky on its feet, slammed obliquely into Earth with terrifying force. That "giant impactor", named Theia, who in Greek mythology was mother to the goddess of the moon, is thought to have been roughly the size of Mars and to have been pulverized in the encounter, along with a good chunk of the proto-Earth. From that fiery cloud of all-Theia and part-Earth, the scenario goes, our moon soon condensed."

Synonyms

All synonyms
greekthea

Example

More examples

"The Moon formed 4.5 billion years ago when a Mars-sized object called Theia slammed into the proto-Earth when our planet was less than 100 million years old, according to leading theories."

Etymology

Borrowed from Ancient Greek Θεία (Theía).

Related phrases

sister wife

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.