A narrow depression, hole, groove, notch, or slit; especially one for receiving or admitting something, as a coin or a letter. Also used figuratively, as in She slotted the new filter into place.

The earliest slot machines had only one reel and were programmed to weight particular symbols, so that they appeared more frequently on the pay line than other symbols. This reduced jackpot sizes and the number of possible combinations, but increased the probability of hitting a winning combination. Charles Fey invented a machine with three reels and an automated payout system that allowed more combinations, and changed the odds so that losing symbols appeared less often than winning ones. He also added a second payline and removed the poker symbols in favor of horseshoes, hearts, diamonds, and liberty bells.

In dialog management, a slot is a specific position within a sequence of events or a timeline. You can identify and map an utterance to a slot by clicking Add Slot Type on the Slots page in the left pane or in the Identified Slots page of the Service Center. You can also add synonyms for a slot type to allow the bot to recognize multiple words and phrases that match its value.

You can also use regular expressions to map values to slots. For example, you can create a custom slot type that matches flight numbers and use it to handle cancellations or changes for your travel bot.