kelh₂-
“to strike, to cut”strike, hew, cut
Root for striking/cutting, yielding Latin clades (disaster), Greek klao (to break), Lithuanian kalti.
Discussion
The PIE root *kelh₂- (to strike, to cut, to hew) produced vocabulary for violent impact and the tools that deliver it — connecting the act of striking to the instruments of combat and construction.
Latin calamitās ("damage, disaster" — originally agricultural destruction, possibly from a striking/cutting catastrophe) may descend from this root, giving English calamity, though the derivation is debated.
Lithuanian kálti (to strike, to forge) preserves the verbal sense directly — the blacksmith's work of striking hot metal.
Old Irish celid ("he conceals" — from a related sense of "cutting off from view") and the related claideb (sword — the cutting instrument, cognate with Latin gladius through a different route) show Celtic reflexes.
The root should be distinguished from *kelh₁- (to call, to shout — the calendar/claim root) and *ḱelh₁- (to rise, to be elevated — the column/culminate root). These three similarly-shaped roots with different laryngeals name different activities: calling (*kelh₁-), striking (*kelh₂-), and rising (*ḱelh₁-). The laryngeal distinction, inaudible in most daughter languages, was meaningful in PIE itself.
Notes
Pokorny 545-546. English calamity, clade, halt, gladiator (via Latin).