requirejs define a module

https://requirejs.org/docs/api.html#define

Define a Module § 1.3

A module is different from a traditional script file in that it defines a well-scoped object that avoids polluting the global namespace. It can explicitly list its dependencies and get a handle on those dependencies without needing to refer to global objects, but instead receive the dependencies as arguments to the function that defines the module. Modules in RequireJS are an extension of the Module Pattern, with the benefit of not needing globals to refer to other modules.

The RequireJS syntax for modules allows them to be loaded as fast as possible, even out of order, but evaluated in the correct dependency order, and since global variables are not created, it makes it possible to load multiple versions of a module in a page.

(If you are familiar with or are using CommonJS modules, then please also see CommonJS Notes for information on how the RequireJS module format maps to CommonJS modules).

There should only be one module definition per file on disk. The modules can be grouped into optimized bundles by the optimization tool.