Full stack development is the process of developing both the frontend and backend of applications. Any application has a frontend (user-facing) component and a backend (database and logic) component. The frontend contains the user interface and code related to user interactions with the application.
Front-end development is the process of building components that interact with users. Examples are the user interface, buttons, user-entered data, websites, and user experience (UX) features.
Back-end development means working on server-side software, which focuses on everything you can't see on a website. Back-end developers ensure the website performs correctly, focusing on databases, back-end logic, application programming interface (APIs), architecture, and servers.
Database, any collection of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval, modification, and deletion of data in conjunction with various data-processing operations.