The Spanish verb 'calzar' (meaning 'to put on shoes') comes from the Latin verb 'calceare', which had the same meaning. 'Calceare' was derived from the Latin noun 'calceus' meaning 'shoe', which in turn came from 'calx' meaning 'heel'. This etymology shows how the word evolved from referring to a body part (the heel) to describing footwear and ultimately the action of putting on footwear.

Several common Spanish words share this root, including 'calzado' (footwear), 'descalzo' (barefoot), and 'calzoncillos' (underwear/shorts). These words all relate to clothing or covering parts of the body, stemming from the original concept of putting on shoes.

While English doesn't have many common words directly related to this Latin root, we do see it in some specialized terms. For example, 'calx' (the same Latin root meaning 'heel') gave us technical terms like 'calcium' (since calcium compounds were historically obtained from limestone) and 'calcify' (to harden by depositing calcium salts). The connection between these words and 'calzar' might seem strange today, but they all trace back to that Latin word for 'heel'!