From PIE meaning 'stone' — a fossil of the Neolithic era when the striking tool was literally a rock, preserved in Old Norse 'hamarr.'
A tool with a heavy head mounted at right angles to a handle, used for driving nails, breaking objects, or forging metal.
From Old English 'hamor,' from Proto-Germanic *hamaraz, possibly from PIE *h₂eḱ-men- ('stone tool, stone weapon'), derived from *h₂eḱ- ('sharp, stone'). The semantic core connects stone implements to striking: the original hammers were shaped stones. Old Norse 'hamarr' preserves a dual meaning—both 'hammer'