automatic

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Acting or operating in a manner essentially independent of external influence or control: an automatic light switch; a budget deficit that triggered automatic spending cuts.
2. adj. Self-regulating: an automatic washing machine.
3. adj. Acting or done without volition or conscious control; involuntary: automatic shrinking of the pupils of the eyes in strong light. See Synonyms at spontaneous.
4. adj. Acting or done as if by machine; mechanical: an automatic reply to a familiar question.
5. adj. Capable of firing continuously until ammunition is exhausted or the trigger is released: an automatic rifle.
6. adj. Semiautomatic: an automatic pistol.
7. n. An automatic machine or device.
8. n. An automatic firearm.
9. n. A semiautomatic firearm.
10. n. A transmission or a motor vehicle with an automatic gear-shifting mechanism.
11. n. Football See audible.
12. idiom. on automatic Functioning by or as if by automatic machine or device.

Century Dictionary and Cyclopedia

1. Acting as an automaton. Having the power of self-motion; self-acting: as, automatic machinery.
2. Conducted or carried on by self-acting machinery.
3. In physiology: Not voluntary; not under the control of, or not effected by, volition: said of certain muscular actions.
4. Not reflex: said, for example, of certain activities of ganglion-cells.
5. n. One who is subject to automatism.

Wiktionary

1. adj. Capable of operating without external control or intervention.
2. adj. Done out of habit or without conscious thought.
3. adj. Firing continuously as long as the trigger is pressed until ammunition is exhausted.
4. adj. computing Automatically added to and removed from the stack during the course of function calls.
5. n. A car with automatic transmission.
6. n. A semi-automatic firearm.

GNU Webster's 1913

1. adj. Having an inherent power of action or motion.
2. adj. Pertaining to, or produced by, an automaton; of the nature of an automaton; self-acting or self-regulating under fixed conditions; operating with minimal human intervention; -- esp. applied to machinery or devices in which certain things formerly or usually done by hand are done by the machine or device itself; The opposite of manual.
3. adj. (Physiol.) Not voluntary; not depending on the will; mechanical; controlled by the autonomic nervous system; without conscious control. The opposite of voluntary.
4. adj. like the unthinking functioning of a machine.
5. n. light machine gun.
6. n. a pistol that will keep firing until the ammunition is gone or the trigger is released.

WordNet 3.0

1. adj. resembling the unthinking functioning of a machine
2. n. a pistol that will keep firing until the ammunition is gone or the trigger is released
3. adj. operating with minimal human intervention; independent of external control
4. adj. without volition or conscious control
5. n. light machine gun