Getting started in Drupal helps to spend some time learning the language. Knowing what names of certain items and actions are helps to understand page structure, architecture, and tools available for managing the website.
There is an overwhelming amount of information here: https://www.drupal.org/docs/8 that you can spend time on. Below are some important terms for management of content.
There are terms relative to Drupal but may really only pertain to the development of a site or architecture of a site. Since Drupal starts very ambiguous and could be used for anything (ecommerce site, blog, application, higher ed school site) It's terms can sometimes be confusing.
Below we've broken down terms by a possible need to know category.
Content and Authoring of content
Block - Blocks are a small unit of repetitive pieces of content that get positioned into a region (left sidebar, header, footer, etc.) of a page. For example, a block containing company contact information could be added to the footer of all pages. Or a block containing related products could be added to product detail pages of an online catalog.
Node - Pieces of content in Drupal, typically corresponding to a single page on the site that has a title, body, and additional fields. Every node belongs to a particular content type and can additionally be classified using taxonomy system. Examples: recipes, articles, partners, etc
NID - Node "ID" an identifier of a node programmatically. nodes start with nid of 1 on the first created node, and increase as you create different nodes. You might see this on editing a page from a human readable "path alias" in the browser bar when editing changing to node/[some number]/edit for example. For example, a node with path, “http://drupal.org/node/937”, has a node ID of “937”.
Content Types - Content of "nodes" is stored by type. Some examples of types if you look in your structure tab will be article, blog post, department, page (web page), etc. Learn more here: https://www.drupal.org/docs/8/administering-a-drupal-8-site/managing-content
Field - Within content types every item entered into a content type is within a field. Drupal has different field "Types" that relate to the way it's stored in a database. See this non-inclusive list. There is quite a few types https://www.drupal.org/docs/7/nodes-content-types-and-fields/add-a-field-to-a-content-type
Image - Images are just files, but uploaded to a specific field type. Output from the content type will go through (optionally) the image system in Drupal to optimize the size and crop / focus of the image to keep it small for different image sizes.
Paragraph - Paragraphs is a system that allows a collection of fields and options onto a content type or block type. It's traditionally used for creation of slideshows with multiple items of the same type, like an image, text, link that can be added as a collection. It's also used to make entering in complex data simpler, or more flexible. Paragraphs can be laid out in sections of the sites regions. Read more about paragraphs on Drupal.org, and learn more about regions and displays if you want to learn more.
PATH - A unique, last part of the URL for a specific function or piece of content. For instance, for a page whose full URL is http://example.com/node/7, the path is “node/7”.
Menu - The navigation or navigations for a website. The menu system in is a hierarchy of drag and droppable elements throughout the sites navigation. Nodes / Pages are not required to be in a menu, and are optionally added to a menu or multiple menus or multiple times into a menu. Menus and nodes operate independent from each other in Drupal.
REVISIONS - Allows you to view previous versions of a node and revert back to a previous item.
PUBLISHED - The state of a node that can be viewed by visitors to the website. To easily hide nodes from the public (i.e. anonymous role), make the node unpublished by unchecking “Published” in the node add/edit form.
WYSIWYG - What You See Is What You Get - the area in which you will be able to enter your content with buttons on the top of the area to add formatting, links, embedded images and media.
WORKFLOW - The process which allows a piece of content to travel through states (i.e. draft, needs review, published)
File - A file field or document you upload, this may not be in the media system. Read more about how files and media work within our documentation.
Media - A document, image, or item in the media system within Drupal. The media system is still early stage, but has a large amount of options to implement on display of media items.
Webforms - Webforms is a module on Drupal which allows you to create forms for users to enter, and email to people. There's also the contact module that builds forms in Core drupal, but has less features although similar
Taxonomy - Taxonomy is Drupal’s system of categorization. Taxonomies are made up of vocabularies which are made up of individual terms.
View - Views are content lists, tables, related content, lists of information on the site created through the views system. Views referenced on a node or content type are created lists that usually display a list of related content, like upcoming events on a page, or related news articles.
File Storage - Private / Public - Files traditionally are stored in directories under /sites/default/files and upload to specific directories by type of file or content type may be configured by the development team. those files are considered "public" files meaning that if you know the URL, you can use the file. Drupal doesn't manage the request from the internet to see the file. Private files are stored in another directory on the web server and if the site visitor has approval by the permissions on the site - Drupal will manage the access to the file by a URL controlled by Drupal.
Cron - Cron is a scheduling system for kicking off tasks on Drupal. It's configured to be ran by the server, or within Drupal at a specific amount of hours. Cron typically does batch processing of tasks like search indexing newly created content, kicking off rules for content notifications, and even automated system rules or membership charges on a recurring ecommerce site for example. It tends to run every 2-3 hours as configured by the developer.
Caching - Caching in Drupal is a method of lowering the amount of requests to the database per visitor. Without caching Drupal would request 200+ requests to the database per page, where with caching it may be 0 or 1 times depending on setup. This speeds up the site to a reasonable level and is a must-have for sites. This core caching should be at least 10 minutes. Outside of Drupal hosts might also provide you with Varnish, Memcache, Redis cache, and other systems to store HTML from the site until it's updated by Drupal and flushed in the external non-drupal caches. https://dzone.com/articles/maximizing-drupal-8-performance-with-nginx-part-ii for how it might work through a web host.
ImageCache - Image cache, like caching creates an appropriate size image for the configured outputs of the image on pages and actually creates a copy of the image to serve up. This image is cached until it is notified that the image has changed, or that the caches are clearing to be rebuilt or flushed. Sometimes you'll see an old image for a short period of time between clearing of the cache through cron for example. It will update.
Search - Search in Drupal by default, uses drupal core search that does an extremely basic search of titles, body and core fields for keywords. It's stored in the database as a search index and when searched, can only do simple search results of that text. Since many people expect a google level of search, there's an ability to programmatically configure modules
Entity - Entities are distinct or independent units of content in Drupal. Common entities include nodes, users, comments and taxonomies.
Theme - The theme is a collection of files and images that make up the design (layout, color scheme, etc) of a Drupal site.
Views - Views is a module that allows users to pull data from the database in a non-technical manner. Using a point-and-click interface, users can generate lists of content while the module does the work of generating the queries behind the scenes. For example, a view could show a list of users that have registered in the past month, or a list of line items on an order form, or a list of unpublished content.
Composer - https://getcomposer.org/ a installation / software management system built for managing software with a large amount of requirements. Many software packages require composer now, and it's basically required to install or update modules anymore in Drupal. If you're administering a website, learn this today.
Symfony - The latest Drupal project (Drupal 8) was completely rebuilt on top of this system https://symfony.com/ in an effort to combine and use code that others have already built, and contribute to a project together with all developers. Notably that means everything that was built before, now has to be rebuilt in the new architecture since it can't plug in with minimal changes. This is why Drupal 7 modules and systems might be more stable or mature / finished than Drupal 8 modules and features.
Feature - Some of Drupal’s configuration settings are stored by default in the database - views settings, site variables, panels layouts, custom fields, etc. Moving these settings back and forth between development, staging, and production databases would be extremely difficult. With the Features module, a developer can bundle related settings together through a point-and-click interface and export them to code. The exported code is downloaded as a module called a “feature” and added to the Drupal site’s codebase where it can be moved between servers and its revisions can easily be tracked.
GIT - The chosen version control system by most open source projects, GIT records each change to the software, additions and deletions of files stored within the system. These files and not content or database information are recorded to ensure the ability to track down programming issues, changes, and updates as the site is updated and upgraded. The version control doesn't have any connection to the actual content or files created or edited by the users.
ROLES - Roles are a grouping of permissions for accessing, creating, editing, and deleting content and managing different aspects of the site. A role is then assigned to a user and that user has the permissions assigned to the role. For example, if a role name ‘editor’ is given the ability to create and edit articles and the editor role is assigned to Ellen, the links to create and edit articles are displayed to Ellen when she is logged in. If Ellen sends Joe a link to edit an article and Joe doesn’t have the editor role assigned to his account, he will be shown an “access denied” message. Users can belong to more than one role.
Permissions - Permissions are yes/no access controls on all aspects of a site. Roles are assigned permissions and can be as granular as a specific field on a content type for view or editing if required. For example a permission to edit blog posts may be granted to the blog author role, where news author role doesn't have those permissions, they won't be able to access the edit screen.
Users - Users are account holders in Drupal. They have a username, email, and password to login to drupal. By default and required in Drupal - all users who have logged in, are authenticated users and will inherit the permissions of such. Anyone who isn't logged in - a site visitor - has the anonymous role. Users can be given roles, and edit their accounts / reset their passwords.
Single Sign On or SSO - By default, the Drupal system manages the authentication of users with just basic admin creation of a user, authentication by encrypted password. Typically that's enough but if not SSO options noted below might be one to add. Note that you can't do all of these, just one per site to manage the authority who is in charge of user management. Many have options to create users and map to Drupal roles if provided by the system. Your system typically is locked away by IT securely and will require coordination to get the right details.
CAS - (not core)
SAML - (not core)
LDAP or Active Directory - (not core)
ADFS - (not core)