'natron' comes from Greek 'nitron' (νίτρον), via Latin and French; the Greek word itself ultimately derives from an Egyptian term for a native sodium-bearing mineral.

'natron' traces back to Egyptian nṯr (a word for a soda/mineral), which passed into Greek as 'nitron', into Latin and Romance languages, and then into modern English as 'natron'.

Originally it referred broadly to native soda salts used for cleaning and preservation; over time it became the name for the specific naturally occurring sodium carbonate (and related salts) mixture now called natron.