/saɪˈkɒlədʒi/
[noun] The scientific study of the human mind and how it affects behaviour and feelings. It covers topics like memory, emotion, personality, and mental health.
Psychology literally means 'the study of the soul' — science only borrowed the word after centuries of philosophy and religion used it first.
The word psychology comes from two ancient Greek roots: psykhē (ψυχή), meaning 'soul' or 'breath of life', and logos (λόγος), meaning 'study', 'reason', or 'word'. Put them together and you get 'the study of the soul' — a definition that feels surprisingly spiritual for a word we now associate with laboratories, clinical trials, and brain scans. The Greek psykhē was itself connected to the verb psykhein, meaning 'to breathe' or 'to blow', because the ancient Greeks believed the soul entered the body with the first breath and left with the last.
The word's earliest recorded use in a modern European language appears in the Latin form psychologia, coined by scholars writing in Latin during the Renaissance period. The Croatian humanist Marko Marulić is sometimes credited with using a version of the term in the late 15th century, and the German philosopher Rudolf Göckel published a work called Psychologia in 1590, helping to establish the word in academic writing. From Neo-Latin psychologia, the word moved into German as Psychologie, into French as psychologie, and then into English as psychology — all following the same pattern, each language borrowing directly from the scholarly Latin form.
English picked up the word in the mid-17th century, with early uses appearing around the 1650s. At first, it sat firmly within the world of philosophy and theology. 'Psychology' was the branch of learning that examined the immortal soul — its nature, its relationship to the body, and its place in God's creation. This was not science in any modern sense; it was closer to what we might now call metaphysics. The idea that the soul could be weighed, measured, or tested in a laboratory would have seemed absurd, even blasphemous, to the word's earliest English users.
The great shift came in the 19th century. As scientific thinking began to reshape how Europeans understood the world, a new generation of thinkers began to ask whether the mind — whatever its ultimate nature — could be studied using careful observation and experiment. The German scientist Wilhelm Wundt opened the first experimental psychology laboratory in Leipzig in 1879, and this moment is often called the birth of psychology as a formal science. Suddenly, the old word had a new job. Psychology shed its theological robes and put on a lab coat, though the ghost of 'the soul' never entirely disappeared from the word's deeper meaning.
The Greek myth of Psyche adds another layer of richness to the word's story. In the myth, Psyche is a mortal woman of extraordinary beauty who becomes the beloved of Eros, the god of love. Her name was used by the Greeks to represent the human soul, and artists across centuries painted her with butterfly wings — because in Greek, the same word psykhē meant both 'soul' and 'butterfly', creatures that emerge transformed from their cocoons, just as the soul was thought to leave the body after death. This poetic connection means that every time a psychologist talks about the mind, they are — without knowing it — speaking the language of ancient myth.
Today, psychology has branched into dozens of specialised fields — clinical psychology, cognitive psychology, social psychology, neuropsychology — and the word appears in dozens of everyday English compounds. The same Greek root psykhē lives on in words like psyche (Greek psykhē → English psyche), psychic (Greek psykhē → Latin psychicus → English psychic), psychiatry (Greek psykhē + iatros 'healer' → Modern Latin psychiatria → English psychiatry), and psychosis (Greek psykhē + -osis 'condition' → English psychosis). Through all these descendants, the ancient Greek breath of life keeps blowing quietly through modern language.