'ecologist' originates from the Greek word 'oikos,' meaning 'house' or 'environment,' combined with the suffix '-logist,' indicating a person who studies a particular field.

'oikos' transformed into the French word 'écologie,' and eventually became the modern English word 'ecology,' from which 'ecologist' is derived.

Initially, it referred to the study of organisms in their environment, and this meaning has largely remained the same in modern usage.