Express.js is a web application framework for Node.js, providing a robust set of features for building web servers and APIs. It simplifies the process of handling HTTP requests, routing, and middleware integration.

AngularJS is a client-side JavaScript framework developed by Google for building dynamic and interactive web applications. It provides two-way data binding, dependency injection, and a modular structure for organizing code.

Node.js is a server-side JavaScript runtime built on Chrome's V8 engine. It allows developers to run JavaScript code on the server, enabling a unified development language for both frontend and backend.

npm (Node Package Manager): npm is a package manager that comes with Node.js, providing a vast repository of open-source packages that can be easily installed and used in your projects.

MongoDB is a non-relational database, which means it does not use the traditional tabular structure like SQL databases. Instead, it stores data in flexible, schema-less documents.

MongoDB organizes data into collections, which are similar to tables in SQL databases. Each collection contains individual documents, which are analogous to rows in SQL databases.

Express.js uses middleware functions to process incoming HTTP requests and responses. Middleware allows you to add functionality to your application's request-response cycle, such as authentication, logging, and error handling.

Express.js enables you to define routes to handle different HTTP methods and URLs, making it easy to structure your back-end application.

Angular supports two-way data binding, which allows data changes in the model to be automatically reflected in the view and vice versa. This simplifies managing data and updating the user interface.