'Cow' traces back 6,000 years to PIE *gwous — one of the oldest continuously spoken words alive.
A mature female of domesticated cattle (Bos taurus), or loosely any domesticated bovine animal. Also used for the female of certain other large animals such as elephants, whales, and seals.
The word 'cow' comes from Old English 'cū,' from Proto-Germanic *kūz, from Proto-Indo-European *gʷṓws, meaning 'cattle' or 'bovine.' This is one of the oldest and most widely attested words in the Indo-European family, with cognates in nearly every branch: Latin 'bōs' (from earlier *gʷōws), Greek 'boûs,' Sanskrit 'gáus,' Armenian 'kov,' Latvian 'govs.' The PIE word may itself be onomatopoeic, imitating the lowing of cattle. Key roots: *gʷṓws (Proto-Indo-European: "cattle,
English 'cow,' Latin 'bos,' Greek 'bous,' and Sanskrit 'gaus' are all the same word — the initial sounds look different because PIE *gʷ became 'c/k' in Germanic, 'b' in Latin and Greek, and 'g' in Sanskrit, following perfectly regular sound laws discovered in the 19th century.