Word of the Week: kost – ‘bone’

Kost is the Czech word for ‘bone’, a word with an unclear prehistory, but it offers us a couple of avenues for doing linguistic archaeology.

Kost is at least a word that Czech shares with other Slavic languages; there’s kostʹ in Russian and kość in Polish. Beyond the Slavic family, however, things get mysterious.

There are a couple of possible candidates for sister words, both of unclear relationship to kost. One is Latin costa, which means ‘rib’. It’s the origin of the intercostal muscles between our ribs. Another is Ancient Greek ostéon ‘bone’, the source of words like osteoarthritis.

If Czech kost and Ancient Greek ostéon are indeed related, we have to explain the initial K of kost. It’s been proposed by experts that this K was once an added prefix or even a relic of a lost sound, which was originally there at the start of ostéon, and which has somehow been preserved in the Slavic words.