This glossary describes terminology and acronyms used in the Backdrop project and by the Backdrop community.

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action #

A function that operates like a stored procedure. The function parameters, if any, are stored in the database and the function is executed by retrieving these stored parameters and calling the function.

anonymous #

A visitor to a Backdrop website who is not currently logged in. Backdrop considers any such visitor as being the anonymous user, with the user ID 0, and belonging to the anonymous user role.


An application programming interface (API) is a particular set of rules and specifications that software programs can follow to communicate with each other. Within Backdrop there is the API Reference which contains documentation for developers.

argument #

A section of the path for a page on a Backdrop website. In the path /node/937 the first argument is , and the second is <937>. Some modules, most notably Views, allow the use of arguments that allow a particular page to vary depending on context.

Article #

One of two content types that are enabled in the standard installation profile. Articles are used for time-sensitive content like news, press releases or blog posts.

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Basic page #

One of two content types that are enabled in the standard installation profile. Typically basic pages are used for static content that can (but are not required to) be linked into the main navigation bar.

Base theme #

A Base theme is a well-written set of CSS and template files that a theme developer can make use of in a new custom theme. Theme developers can make sub themes to override the default base theme.


Binary Large Object. A collection of binary data stored as a single entity in a database management system.

block #

The boxes visible in the regions of a Backdrop website. Most blocks (e.g. recent content) are generated on-the-fly by various Backdrop modules, but they can be created in the custom blocks area of a Backdrop site.

BoF #

Birds of a Feather. An informal discussion group. Unlike special interest groups or working groups, BoFs are informal and often formed in an ad-hoc manner. BoF meetings are common adjuncts to planned "sessions" at Backdrop Camps.

book #

A set of pages tied together in a hierarchical sequence, perhaps with chapters, sections, subsections, and so on. You can use books for manuals, site resource guides, Frequently Asked Questions (FAQs), or whatever you'd like. To use books, enable the core Book module.

branch maintainers #

See core committers

breadcrumbs #

The set of links, usually near the top of the page, that shows the path you followed to locate the current page. For example, it might show Home > Macadamia Nuts > Current Events > News Articles, meaning that you started at the home page, clicked on in the menu, then selected in the sub-menu, and finally selected, The term breadcrumbs is borrowed from Hansel and Gretel, who left crumbs of bread along their path so they could find their way back out of the forest.

bundle #

A specific implementation of an entity type. For example, the node entity type has bundles called content types. Default node bundles are "page" and "article".

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cache #

The core Backdrop cache stores assembled pages and blocks for anonymous visitors in the cache tables in the database.

callback #

The mechanism for registering a path so that the correct function is fired when the URL is accessed. They are not shown in the menu.

camp #

A camp is a one to two day event that focuses on many aspects of Backdrop in one location. Its focus is knowledge sharing amongst the community. Essentially, you're getting the community together to do some community training.

child #

Objects that can have hierarchical relationships, such as menu items, book pages, taxonomy terms and so on. A menu item, for example, is nested under another menu item, which is referred to as the menu item.

clean URL #

A URL that does not contain code. By default, Backdrop uses and generates URLs for your site's pages that look like <> By enabling clean URLs this will be rewritten to <>.


Content Management System. In the context of a Web site. a collection of tools designed to allow the creation, modification, organization, search, retrieval and removal of information.

code freeze #

The date at which no new features can go in the next version of Backdrop, unless specific dispensations have been made by the core committers (even then, only when the impact on other systems is minimal). At code freeze, the focus in Backdrop core shifts to bug fixing and usability improvements. It is the time when contributed module developers can begin working on updating their code to work with the next version of Backdrop.

commit #

Process of applying a change in a project's code to the Git repository where the project is kept, so that this change is recorded as part of that project's development history.

configuration management #

Backdrop comes with a file system-based configuration management system, which provides tools for transporting configuration changes such as new content types, fields, or views from a development server to a production server (or similar). It even lets you use version control for your configuration. Save your config data from the database to files.

content #

The text, images, and other information on a web site. Besides nodes there is more content on a typical Backdrop site, such as comments and file attachments.

content type #

Every node belongs to a single or , which defines various default settings for nodes of that type, such as whether the node is published automatically and whether comments are permitted. Common "Content Types" that just about any website would have include: blog post and page. Content types can have different fields and modules can define their own content types. The core Backdrop Book and Poll modules are two examples of modules that define content types.

contrib #

Contributed. Modules or themes that are not part of the core Backdrop product. Contributed modules and themes are available for separate download from the Backdrop GitHub Contrib section. Similar concepts exist in other software and are sometimes called , or .

core #

The files and modules included with the Backdrop project download.

core committers #

Backdrop developers that review proposed changes to the Backdrop core and maintain code. They are the only ones who have write access to the core Git repository.

core contributor #

Developers who contribute code patches or documentation for the Backdrop core. Contributions are peer reviewed and then evaluated by the core committers.

core maintainers #

See core committers

critical path #

The code that is run when serving a cached page.

cron #

A command scheduler that executes commands or scripts (e.g. scripts to backup a database) automatically at specified time and date intervals. Backdrop uses a to perform periodic tasks that help Backdrop to run smoothly and efficiently.

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A popular open source CMS product. Backdrop was forked from Drupal version 7 in 2013.


Drupal 6. Any version 6 of Drupal, including all minor versions 6.x.


Drupal 7. Version 7 of Drupal, which includes any minor version, e.g. Drupal 7.0, Drupal 7.23


Drupal 8. Version 8 of Drupal, which includes any minor version, e.g. Drupal 8.0.0

delta #

An index for fields, blocks, etc., of the same type.

DO, D.O. # The website of Drupal.

Drop #

The Backdrop mascot. Also known as Dragon Drop, a play on the expression Drag-n-drop.

DX #

Backdrop Developer Experience.

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entity #

Any defined chunk of data in Backdrop. This includes things like nodes, users, taxonomy terms, files, etc. Contributed modules can define custom entities. Each entity type can have multiple bundles.

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The Backdrop Forms API.

field #

Elements of data that can be attached to a node or other Backdrop entities. Fields commonly contain text, image, or terms.

filter #

A tool for stripping out HTML, PHP, JavaScript, and other undesirable elements from content before pages are displayed. Other filters add formatting and features such as smilies. It is possible to create custom filters that allow or forbid only those tags you wish.

flag #

A way to mark an information item for selection for further processing on this is done for flagging issues.

foobar #

A common placeholder name, e.g. for names of variables (<$foobar>) or functions ().

fork #

A copy of source code from one software package that receives independent development, thus creating a distinct piece of software.

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GDO # The site that serves the Drupal community by providing a place for groups to organize, plan and work on projects. Real world local user groups in particular are encouraged to setup their online presence at GDO.

Git #

A version control system used by Backdrop code contributors to coordinate their individual code changes. Git records everyone's changes to a given project in a directory tree called a git repository.

GitHub #

GitHub is a web-based Git repository hosting service, which offers all of the distributed revision control and source code management (SCM) functionality of Git as well as adding its own features. (Wikipedia). Backdrop uses GitHub to organize and distribute Backdrop core and contrib projects.


Graphical user interface. A program interface that takes advantage of the computer's graphics capabilities to make the program easier to use.

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The current development version of core or a module.

hook #

A PHP function that is named foo_bar(), where is the name of the module (whose filename is thus foo.module) and is the name of the hook. Each hook has a defined set of parameters and a specified result type.

human readable #

Also user-friendly name. The text string used to identify a resource as displayed in the user interface, as opposed to the machine name used for internal purposes of the computer program.

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input format #

A tool for defining the processing that happens to user-entered text before it is shown in the browser. Usually different user roles are given permission to use different input formats depending on how much they are trusted. For those roles, the input format may often be available as an option that shows up underneath the body of a node edit form.

i18n #

Numeronym for internationalization, replacing the 18 middle letters with <18>. Internationalization refers to enabling translations and other-language support (including alternate character sets and right-to-left rendering) in computer systems.


Internet Relay Chat. A network protocol that allows people to chat in real time over the Internet. Backdrop discussions are often going on in The Backdrop IRC Channels

issue #

A unit of work to accomplish an improvement in a data system. An issue could be a bug, a requested feature, task, missing documentation, and so forth. The Backdrop community uses the issue queue to work as a team. If you need help with a specific project, whether it is a module or theme, you should go to the contrib issue queue.

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l10n #

Numeronym for localization, replacing the 10 middle letters with <10>.


Linux, Apache, MySQL and PHP. LAMP is an interoperable group of open-source computer programs that form the most common environment to run Backdrop on.

Layout #

The drag-and-drop page Layout module in Backdrop core which allows end-users to support different arrangements of page regions based on paths and other conditions, and to easily rearrange block positions on a page or set of pages. Layout module ships with several standard "layouts".

layouts #

A collection of files which define a particular page region arrangement for a Backdrop site, for use by Layout module. Core ships with several standard layouts and others can be found in contrib.

legacy code #

A no-longer supported version of Backdrop. The term can also mean code inserted into modern software for the purpose of maintaining an older or previously supported feature.

log #

A list of recorded events. A log may contain usage data, performance data, errors, warnings and operational information. Backdrop's events are logged by the modules dblog and syslog.

library #

A library of code from a third party.

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machine name #

Also machine-readable name. The text string used by the computer to identify a resource, as opposed to the human readable name shown in the user interface.

maintainer #

Single community person which is responsible for the module, also has the right to commit a patch into module. Can be multiple people per module.

menu #

In Backdrop, the term refers both to the clickable navigational elements on a page, and to Backdrop's internal system for handling requests. When a request is sent to Backdrop, the menu system uses the provided URL to determine what functions to call.

migrate #

Moving content from other sources into Backdrop or from one version of Backdrop to another.

module #

Software (usually PHP and CSS) that extends Backdrop features and functionality. Backdrop distinguishes between <core> and <contributed> modules.

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Node ID. The unique identifier for each node. It can be found in the path to the node. For example, a node with path, <>, has a node ID of <10>.

node #

A piece of content in Backdrop, typically corresponding to a single page on the site, that has a title, an optional body, and perhaps additional fields. Every node also belongs to a particular content type, and can additionally be classified using the taxonomy system. Examples of nodes are polls, stories, book pages and images.

node type #

See content type.

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Object Oriented Programing #

The focus of object-oriented programming it is to break down a programming task into objects that expose behavior (methods) and data (members or attributes) using interfaces. The most important distinction between procedural and object oriented programming is that procedural programming uses procedures to operate on data structures, object-oriented programming bundles the two together so an "object", which is an instance of a class, operates on its "own" data structure.

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page #

See Basic Page People also use the word "page" to mean a web page (i.e., a page you get to by navigating to a specific URL on a web site).

parent #

See child

patch #

A small piece of software designed to update or fix problems with a computer program or its supporting data. This includes fixing bugs, replacing graphics and improving the usability or performance.

path #

In Backdrop terms, a unique, last part of the URL for a specific function or piece of content. For instance, for a page whose full URL is, the path is . Backdrop can use clean URLs if the Path module is enabled, which would change the full URL in this example to; the path would still be .

permission #

In Backdrop, a tool for controlling access to content creation, modification and site administration at the application level. Administrators assign permissions to roles, then assign roles to users. The first user of a Backdrop site (User1) automatically receives all permissions. In operating systems like UNIX, permissions are security settings restricting or allowing users to access information or perform certain functions at the operating system level. In the case of files on UNIX systems, there are three types of permissions: read, write and execute.

Procedural Programing #

The focus of procedural programming is to break down a programming task into a collection of variables, data structures, and subroutines. The most important distinction between procedural and object oriented programming is that procedural programming uses procedures to operate on data structures, object-oriented programming bundles the two together so an "object", which is an instance of a class, operates on its "own" data structure.

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 in the node add/edit form.

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queue #

A job management technique. Jobs waiting in a line (queue) are usually processed on a first in, first out basis or by priority, if specified. The Backdrop community uses the issuequeue to work as a team. If you need help with a specific project, whether it is a module or theme, you should go to the issue queue.

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reference field #

A type of field that allows authors to create a relationship between an entity and one or more other entities. For example, authors might "tag" an article with taxonomy termsusing a Term Reference field. Other reference fields can be used to define other kinds of relationship (for example, between nodes and other nodes, or nodes and users). Depending on the Backdrop version and/or contributed modules installed, these might be called Entity Reference, Node Reference or User Reference fields.

region #

Defined areas of a page where content can be placed. Basic regions include: Header, Footer, Content, Left sidebar, Right Sidebar. Regions are determined by the active layout for the page being viewed. Content is assigned to regions via blocks. They can be ordered by weight within regions to define the order in which they display. Todo

render array #

Render arrays are the basic building blocks of Backdrop content. In Backdrop, render arrays provide a structured way to programmatically alter content before it is displayed.

repository #

In revision control systems, a repository is an on-disk data structure which stores metadata for a set of files and/or directory structure. (Wikipedia). Git projects are kept in repositories.

reroll #

Reimplementing of code on top of HEAD of a code repository, mostly because HEAD has changed.

roles #

Sets of permissions that can be applied to individual users. Users can belong to more than one role. Two roles, authenticated users (those users that sign up for an account) andanonymous users (those either without an account or not logged in), are supplied by default with Backdrop installations. Backdrop allows creating additional roles.


Really Simple Syndication. A family of Web feed formats used to publish frequently updated content such as blog entries, news headlines or podcasts. An RSS document (which is called a or or ) contains either a summary of content () from an associated web site or the full text. RSS is one of the many ways of connecting a Backdrop website with external sites, systems and data.


Reviewed and tested by the community. RTBC is one of the statuses given to issues in the issue queue.


Right-to-left. Languages such as Arabic and Hebrew run from right to left across a written page, and need to do the same on a web browser. RTL support can be problematic in theme design, but is possible.

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sprint #

A meeting where people meet gather at a specific time to discuss and work on software development tasks. A code sprint is a typical element of a Backdrop event.

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tag #

See term.

tar.gz #

Tape archive. A file format and the name of the program used to handle such files. Backdrop projects are distributed in Zip and tar.gz formats. A *.tar.gz file is a combination of two technologies: Tar - create the file and Gzip - compress the file (similar to zip).

taxonomy #

In Backdrop, "Taxonomy" is the name of a powerful core module that gives your sites use ofterms. In Backdrop, these terms are gathered within vocabularies which the Taxonomy module allows you to create, manage and apply.

teaser #

A short introductory sentence or paragraph about a piece of content that informs readers about the subject of the content. By default, the first paragraph or two of the content is used (there is a setting for how much), usually with a link to the complete node.

template #

A file to express presentation (vs. program logic). Templates are mostly HTML with special PHP variables. The variables in templates substitute in values provided by a theme engine.

term #

An organizational keyword, known in other systems as categories or metadata. A term is a label that can be applied to a node. They are also known as tags.

theme #

A file or collection of files (PHP, INFO, CSS, JPG, GIF, PNG), which together determine the look and feel of a site. A theme contains elements such as the header, icons, block layout, etc. Backdrop modules define themeable functions which can be overridden by the theme file. There are additional themes available in the themes section of downloads. Todo

theme engine #

A set of scripts that interprets code and makes theming a site easier. These scripts take the dynamically generated content and output it to HTML. The Backdrop theme engine is phpTemplate.

trigger #

Defined by modules, triggers typically result from some characteristic change in an entitymaintained by a module. Some examples of triggers are: deleting content, adding acomment that a user has logged in, or adding a term. The Trigger module was removed from Backdrop core.

triage #

A new bug or issue is assigned a priority based on its severity, frequency, risk and other predetermined factors, borrowed from medical term triage.

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User ID. The unique identifier for each user. It can be found in the path to the user profile, e.g. <>

unpublished #

See published

update #

Moving from one minor release to another, e.g. moving from Backdrop 1.0.2 to Backdrop 1.0.3.

upgrade #

Moving from one major release to another, e.g. moving from Backdrop 1 to Backdrop 2.


uniform resource locator. The address that defines the route to locate an object on an Internet server. Generally, the syntax for a URL contains the scheme, host-name, port, path and filename, e.g.

user1 #

The first user created on installation and granted additional (all) permissions. This user is referred to as the site maintenance account in Backdrop.

UX #

user experience. An umbrella term referring to the overall experience and satisfaction a user has when using a website. It is important to note that this

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Views #

A module which allows site developers a simple graphical interface for creating lists of various Backdrop objects; most notably users and nodes. Views permits selection of specific fields to display, filtration against various node attributes, choice of basic layout options (i.e. list, full nodes, teasers, etc.), and other more advanced features.

vocabulary #

A vocabulary is a collection of terms.

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weight #

A term used by Backdrop to define the priority or order in which a function is processed or a block / node is displayed. From Backdrop 6, the weight field is adjusted dynamically using a drag-and-drop interface. Note: A lower weight value (-10) will float to the top of lists, while heavier (+10) weights will appear lower in lists.


a field api and cck term used to refer to the HTML form element used to collect the input for the field from the user.


What You See Is What You Get. An acronym used in computing to describe a method in which content is edited and formatted by interacting with an interface that closely resembles the final product.

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zebra striping #

Alternating colors behind rows of data. This is often used in tabular data where rows of data alternate background colors between white and a shade of gray.

Zip #

The zip file format is a data compression and archive format. A zip file contains one or more files that have been compressed, to reduce file size. Backdrop core and modules are offered both in the zip and tar format.

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This document is adapted from the Drupal Glossary page.