ǵʰésr̥
“hand, grasping limb”hand, grasp
Root for hand, yielding Greek kheir, Hittite kessar, Tocharian A tsar.
Discussion
The PIE noun *ǵʰésr̥ (hand, grasping limb — an r/n-stem heteroclitic) is one of the most archaic body-part terms in the reconstructed vocabulary, belonging to the same ancient declension class as *wódr̥ (water) and *péh₂wr̥ (fire). The alternation between *-r in the nominative and *-n in the oblique cases preserves a nominal pattern that was already archaic in PIE itself.
Greek kheír (χείρ, genitive kheirós, "hand") is the most productive Hellenic reflex: chirurgy (kheirourgia, "hand-work" — the original term for surgery, literally working with the hands), chiropractor (kheír + praktikós, "hand-practitioner"), chiromancy (hand-divination, palm reading), and the combining form chiro- in medical and zoological terminology. The related Greek enkheirídion ("something in the hand" — a handbook, a manual, a dagger) gave English enchiridion.
Hittite kiššar- (hand) provides crucial Anatolian attestation, preserving the heteroclitic declension pattern with unusual clarity. The Hittite evidence confirms the initial palato-velar *ǵʰ (reflected as Hittite k-) and the r/n-stem alternation.
Old Irish gaiscedach (warrior — from gáe, spear, + a form related to the hand/grasping root) may provide Celtic attestation, though the precise derivation is debated.
The Germanic branch does not clearly continue this root as the word for "hand" — English hand (OE hand/hond) is of uncertain PIE etymology, possibly from *ḱent- (to seize). The replacement of the inherited hand-word in Germanic parallels the replacement of the inherited horse-word — both core vocabulary items that were unexpectedly abandoned in the Germanic branch.
The heteroclitic declension (*ǵʰésr̥/*ǵʰsnés) is itself a subject of theoretical importance. The r/n-stem nouns were an archaic PIE class typically reserved for basic substance and body-part terms: water, fire, liver, and hand all belong to this pattern. Their grammatical archaism may reflect their semantic age — these were words so fundamental that they preserved inflectional patterns that had become unproductive in later PIE.
Notes
Pokorny 447. Heteroclitic r/n-stem.