A script is a pretty vague term, generally, a script is a group of code that preforms in and around a root goal, like a script to generate a json file that has some input parameters which slightly modify the final output.
In PHP, you might have one main script in your project, or you may have many fragments – there is not hard line that says what is a script.
You may even call other scripts from yours; voting to close as opinion based.
solved What is the actual meaning of “script” in php? [closed]