Here is a list of terms used in these Content type tutorials:

Content type Content types are the building blocks of your web pages and are where you add your content, whether that is text, images or videos. There is a full A-Z list of content types.
Page layout T4 term for a page template. There are currently three landing page lyouts and one content layout.
Responsive website Website that works on all screen sizes and types, eg. mobiles, tablets, desktop etc.
Section T4 name for a web page or folder
Sub-section T4 name for a sub-page or sub-folder (Also known as a 'Child').
Branch A sections (page) including all of its sub-sections.
Site Manager The name t4 gives their CMS
Site structure Main t4 Site Manager screen, a view of the site structure and the starting point for building or adding to sections (pages). It can also be called the site tree.
Moderator The Moderator role gives you the right to add content; modify content, delete content and add to the Media Library. Plus approve content, create a Site Structure and publish.
Power User The Power User role gives you the same rights as the Moderator, plus assign and create new users, navigation, templates and footers.
Administrator The Administrator role gives you the same rights as the Super User, plus manage users, styles, workflows and templates, assign and create new users, run reports, have Access Control and set configurations.
 TinyMCE The name of the text editor used in some of the content types including General content, accordions and tabs.