h₂eyd-
“to burn, fire”burn, glow, fire
Root for burning, yielding Latin aedes (hearth/temple), Greek aithein (to burn), English edify.
Discussion
The Proto-Indo-European root *h₂eyd- meant "to burn" or "to kindle." Latin aedēs originally meant "hearth" or "fireplace," the burning center of the home, and only later expanded to mean "dwelling" and then "temple" — a progression tracing the architectural history of Roman religion. The related aedificāre, "to make a hearth," gave English edifice, making every building etymologically a place where fire burns. Greek aíthein, "to burn," produced aithḗr, the upper air conceived as luminous burning substance, which entered English as ether. The geographical name Aithiopía (Ethiopia) meant "land of burnt faces." The root also appears in Aetna, the burning mountain. Sanskrit édhas means "fuel" and índhē means "to kindle," preserving the practical domestic sense. Watkins emphasizes that *h₂eyd- belonged to the everyday vocabulary of fire-tending rather than the poetic register, which was served by *péh₂wr̥ (fire as substance). Yet even this humble hearth-word achieved transcendence: from kindling a cooking fire to naming the luminous substance of the cosmos, *h₂eyd- traces the human impulse to see in every domestic flame a fragment of the celestial fire above.
Notes
Pokorny 11-12. English edify, ether, estuary, estival.