Uncertain. There are various possibilities.
- a substrate pre-Indo-European word with no recorded or surviving cognates (words for technologies are retained, otherwise we would have expected Albanian to have borrowed the word for iron by one of the many neighbors, invaders or directly fro PIE)
- a substrate word cognate to Old Armenian երկաթ (erkatʿ), via a proto-form with metathesis *herku
- related to hekë, from Proto-Indo-European *skek- 'to jump, be agile', thus 'to tremble, shiver', literally 'that which trembles, jingles', with a semantic development similar to kërcej, meaning both 'to jump, dance' and 'to make a cracking sound'.
- an irregular cognate of Greek ἄγκυρα 'anchor'.
- iron (the metal)