The Spanish word 'pelao' (a colloquial form of 'pelado' meaning 'bald' or 'hairless') traces back to the Latin word 'pilus' meaning 'hair'. From this root, Latin developed the verb 'pilare' meaning 'to remove hair'. This evolved into the Spanish verb 'pelar' meaning 'to peel' or 'to remove hair', from which we get the adjective form 'pelao'.

This evolution shows an interesting semantic development where a word derived from the noun for 'hair' came to describe the absence of hair through the intermediate step of a verb meaning 'to remove hair'.

Several common Spanish words share this root, including 'pelo' (hair), 'peluquería' (hair salon), and 'peludo' (hairy). The verb 'pelar' is also commonly used in cooking contexts to mean 'to peel' (as in peeling fruits or vegetables). All these words maintain a connection to either hair or the concept of removing an outer layer.

While English 'peel' might seem related, it actually comes from a different Latin root. However, English words like 'depilatory' (a substance used to remove hair) and 'pileous' (relating to hair) do come from the same Latin root 'pilus'. The medical term 'alopecia' (hair loss) also relates to this word family, though it comes through Greek rather than Latin.