Unlike in Rails, Meteor projects don’t have a rigid file structure and you are pretty much free to organize your projects as you want. A few folder names however have special meaning, and files within them will be treated differently.
Files here will be loaded on the client only. Files in that folder don’t need things like Meteor.isClient.
Loaded on the server only, duh! No need for Meteor.isServer when files are in that folder, the client won’t see these files.
This directory is for assets like images. In your projects, you reference stuff in the public folder as if they were in the root folder. For example, if you have a file: public/nude.jpg, then in your app you include it with <img src=”nude.jpg”>.
Files only accessible on the server side through the Assets API.
Files in there won’t be loaded anywhere and are used for testing your app.
Files in that folder are loaded before anything else, which makes it the perfect directory to place the different libraries used on a project.