Course Blocks (aka xblocks, components)
This document outlines the key objects that make up a course.
The course outline is the container for all of your course content. The outline contains one or more sections.
Course sections are at the top level of your course and typically represent a time period (chapter) . A section contains one or more subsections.
Course Subsections are parts of a section, and usually represent a topic or other organizing principle( i.e lesson, topic, small unit of work). A subsection (aka sequential) contains one or more units.
Units are lessons in a subsection that learners view as single pages. A unit contains one or more components.
Components are objects within units that contain your actual course content( i.e. problem, video, discussion, or other content blocks).