slot machine

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A gambling machine operated by inserting coins into a slot and often by pulling down on a long handle.
• noun A vending machine operated by inserting coins into a slot.

from The Century Dictionary.

• noun A machine for vending small articles of merchandise, exhibiting pictures, weighing, playing musical instruments, etc., which is either unlocked or set in motion by dropping a coin into a slot. See vending-machine.

from the GNU version of the Collaborative International Dictionary of English.

• A machine the operation of which is started by dropping a coin into a slot, for delivering small articles of merchandise, showing one's weight, exhibiting pictures, throwing dice, gambling, etc.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any machine operated by placing a coin or token into a slot.
• noun A gambling machine so operated; a fruit machine or one-armed bandit.
• noun A vending machine.
• noun poker slang three of a kind sevens

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a machine that is operated by the insertion of a coin in a slot