'ammonium' originates from 'New Latin', specifically the word 'ammonium', where 'ammon' referred to the ancient Egyptian god Amun, associated with the ammonium chloride found near the temple of Amun.

'ammonium' was derived from the Latin word 'ammoniacus', which referred to the salt of Ammon, and eventually became the modern English word 'ammonium'.

Initially, it referred to the salt of Ammon, but over time it evolved into its current meaning of a positively charged ion (NH4+).