'tiara' originates from Latin, specifically the word 'tiara', which was borrowed from Ancient Greek 'τιάρα' (tiára), meaning a type of headdress.

'tiara' changed from the Greek word 'τιάρα' to the Latin 'tiara', and eventually became the modern English word 'tiara'.

Initially, it meant 'a type of headdress', and over time it evolved into its current meaning of 'a decorative headpiece'.