A hero block or region is a block that stretches from one side of the screen to the other. The content in a hero block is not necessarily constrained to the defined content width in other blocks or regions. You may see an option to add an "container" class to a block or region. Doing this should help constrain your content to the default content width for your site.
A module is plug-in that adds functionality or features to Backdrop CMS. Some modules have a large visible impact on the site, others add hidden features that are used by still other modules.
A individual piece of content. An individual blog post, article, or page is a node.
Views are created by the views module that is included in Backdrop CMS core. Views are dynamic displays of your data that allow you to create filters, sorts, and choose which fields to include in each individual view.