h₂eḱsmen-
“stone, thunderbolt”stone, thunderstone
Extended form of *h2ek- for stone, yielding Latin acumen, Greek akmon (anvil).
Discussion
The root *gʰeyH- carries the meaning "to release, to let go, to propel forward," encoding the act of loosing something from constraint — an arrow from a bowstring, a word from the mouth, a person from a place. Rix (LIV² 195) reconstructs the root with the laryngeal, and Pokorny (IEW 418–419) documents its reflexes across several branches, though the family is smaller and more debated than many PIE roots.The most consequential reflex may be the Germanic verb that became English go, though this attribution is contested. Some scholars derive Old English gān from *gʰeyH- through a semantic path of "to release oneself, to set forth," while others prefer an independent root. What is less disputed is the connection to Greek khainō "I gape, I yawn" — the mouth releasing, opening wide — which Beekes (EDG, s.v. χαίνω) links to *gʰeyH- with the sense of "gaping open," a metaphorical extension of releasing or letting go. From this Greek branch English inherits chaos (originally "the gaping void") and chasm.The Indic evidence includes Sanskrit jihīte "he goes forth, he departs," which preserves the root's sense of directed release — departure as the act of letting go of a place. Watkins (AHDIER, s.v. *ghē-) treats the root as fundamentally about propulsion and release, noting that its reflexes cluster around two poles: physical departure and oral opening. The root captures a proto-conceptual link between going and gaping, between exit and utterance — both understood as acts of releasing from enclosure.
Notes
Pokorny 18-22. Compare hammer from same extended root.