In data modeling, we use the term entities to represent the things that we want to store in the database, and these things exist either physically or logically and can be uniquely identified. Entities are abstractions of the complexities of the things, a domain, that you're modeling. And, usually, they consist of only those characteristics that the application you're developing is interested in. For example, in the TaskAgile application, User entities represent the users of the application whose data needs to be stored in the database. During physical data modeling, if you're targeting an RDBMS, such as MySQL, these User entities will be stored inside a table, and each User entity will be a record of that table. Or, if you’re targeting a NoSQL database, such as MongoDB, they will be stored inside a collection, and each User entity will be stored as a document inside that collection.