Roots/*h₂eḱsmen-h₂eḱsmen-“stone, thunderbolt”Debatednatureearthstone, thunderstoneExtended form of *h2ek- for stone, yielding Latin acumen, Greek akmon (anvil).Related Roots(s)teh₂n-“to thunder”Hreg-“to wet, to rain”angʷʰi-“eel, snake, water-serpent”bʰerǵ-s-“to protect by enclosing”bʰew-sis-“nature, growth, being”bʰew-tú-“growth, nature, coming-to-be”bʰleh₁-“to blow, to puff”bʰudʰ-men-“bottom, foundation, ground”