'psychological' originates from Greek, specifically the word 'psychologia,' where 'psyche' meant 'soul' and 'logia' meant 'study of.'

'psychologia' transformed into the French word 'psychologique,' and eventually became the modern English word 'psychological' through Middle English.

Initially, it meant 'study of the soul,' but over time it evolved into its current meaning of 'relating to the mind or mental processes.'