Slots
To allow the chatbot to be really useful, it has to be able to gather details about what the user is asking for. If you are wanting to order a pizza, the chatbot needs to know what toppings you want, what style of base you want, and where you want it delivered to. This information is collected and stored in slots.
Slots are designed to only accept certain types of information. If you were trying to find out whether they wanted a large, medium, or small pizza, it wouldn't be very useful if they could enter any random information. Defining the information that can be stored in a certain slot is called creating a slot type.
To make use of the information gathered in the slots, they can be accessed in the next stage of the chatbot logic. This could be as simple as saying "You have ordered a large Hawaiian pizza", where the size and topping are exactly what the user previously ordered.