Definition of "Automatic" :

noun: a pistol that will keep firing until the ammunition is gone or the trigger is released

noun: light machine gun

adjective: operating with minimal human intervention; independent of external control

"Automatic transmission."

adjective: resembling the unthinking functioning of a machine

"An automatic thank you'."

adjective: without volition or conscious control

"The automatic shrinking of the pupils of the eye in strong light."