'autism' originates from Greek, specifically the word 'autos', where 'autos' meant 'self', combined with the suffix '-ism' (from Greek '-ismos' via Latin and French) denoting a condition or practice.

'autism' changed from the German medical term 'Autismus' (used in early 20th century) and was adopted into English medical literature—notably used by psychiatrists such as Eugen Bleuler and later by Leo Kanner—to become the modern English word 'autism'.

Initially used to describe a withdrawal into the self (Bleuler's description in relation to schizophrenia), its meaning evolved to denote a distinct neurodevelopmental condition ('autism spectrum') as currently used in clinical and everyday language.