'extraterrestrial' originates from Latin, specifically the word 'extraterrestris,' where 'extra-' meant 'outside' and 'terrestris' meant 'of the earth.'

'extraterrestris' transformed into the French word 'extraterrestre,' and eventually became the modern English word 'extraterrestrial' through Middle English.

Initially, it meant 'outside the earth,' and this meaning has largely remained the same in modern usage.