Any machine that performs the functions of a bank teller; (now especially) a machine that automatically provides cash and performs some other banking services on insertion of a special card; = "ATM".
Origin
1920s.
Definition of automatic teller in US English:
automatic teller
noun
US
Any machine that performs the functions of a bank teller; (now especially) a machine that automatically provides cash and performs some other banking services on insertion of a special card; = "ATM".