'eternalist' originates from the English word 'eternal,' which comes from the Latin word 'aeternalis,' where 'aeternus' meant 'eternal.'

'aeternalis' transformed into the Old French word 'eternel,' and eventually became the modern English word 'eternal,' from which 'eternalist' is derived.

Initially, it meant 'pertaining to eternity,' but over time it evolved into its current meaning of 'a person who believes in eternal existence.'