What does the "as build" keyword mean after the image version?

I have a simple Docker config file.

FROM nexus.something.local:<my port>/v1/repositories/local_node:14.17.5 as build

What does the as build keyword mean in here? I can’t find anything about this configuration from the Docker documentation.

>Solution :

The as option allows you to name the stage, which is useful when working with multi-stage builds:

https://docs.docker.com/build/building/multi-stage/#name-your-build-stages