Gaia or Gaea derives from the Greek words Ge (γη) = Earth (Pelasgian), and *aia = grandmother (PIE). Thus, Gaia (γαια) can refer to any one of the following:

• Gaia, a goddess from Greek mythology; also Terra or Tellus, her equivalent in Roman mythology, and Ki, her equivalent in Sumerian mythology
• Gaia hypothesis - an ecological hypothesis that proposes that living and nonliving parts of the earth are viewed as a complex interacting system that can be thought of as a single organism
  • Gaia's Revenge - features studies forecast about unintended consequences of brewing climate storms
• Gaia philosophy, a set of philosophical views based on ecosystems and the concept of a "living planet"
• Gaia Movement - international network of groups drawing inspiration from the Gaia hypothesis