When an intent is matched, Dialogflow can extract specific information from the end-user expression. The extracted data is called a parameter or entity type. Parameters and entity types are structured data that can help us make better sense of what the user is trying to find out.
In Dialogflow, there are system entities - e.g. dates, times, numbers, email addresses, etc. You can also create your own custom entities. For example, you could define a vegetable entity that can match the types of vegetables available for purchase with a grocery store agent.
