MongoDB is an open-source, document-oriented database that is cross-platform compatible and designed to work with data in JSON and similar formats. It is a type of NoSQL database that is used for managing large volumes of data. The name “Mongo” comes from “Humongous,” describing the data size the software is meant for. While MongoDB may not be the ideal choice for everyone, it is a powerful type of database system that many organisations handling large-scale or complex data prefer to work with due to its flexibility and scalability.