backend
n. countablen. the part of a website or software program that you cannot see. It handles the data, servers, and behind-the-scenes work that makes the app run smoothly.
n. the underlying data access and processing layer of a software application, inaccessible to the end user. It typically consists of a server, an application, and a database.
The team is updating the backend to make the website load faster.
While the design looks great, the developers still need to build a secure backend to store customer passwords and process payments.
Migrating the legacy backend to a cloud-based infrastructure reduced server downtime significantly, though it required rewriting several core APIs to ensure seamless communication with the frontend.
Frequently contrasted with 'frontend' and often used attributively, as in 'backend developer' or 'backend system'.