Psychology is the studey of mind. The word itself comes from the Greek root psyche, meaning 'the mind or soul', and the suffix-ology, from the Greek logos, meaning 'they study of'. The term 'psychology' was not cioned tnto popular use in the. Eighteenth century. In fact psychology was not practised as an explicitly identified discipline until the late nineteenth century. Its roots, however, can be traced back much further than this.