terms.html

<p>While some terms are defined in place, the following definitions are used throughout this document. </p>
<dl class="termlist">
    <dt><dfn data-lt="accessibility api|accessibility apis">Accessibility <abbr title="Application Programming Interface">API</abbr></dfn></dt>
    <dd>
      <p>Operating systems and other platforms provide a set of interfaces that expose information about <a class="termref" data-lt="object">objects</a> and <a class="termref" data-lt="event">events</a> to <a>assistive technologies</a>. Assistive technologies use these interfaces to get information about and interact with those <a class="termref" data-lt="widget">widgets</a>. Examples of accessibility APIs are <a href="https://docs.microsoft.com/en-us/windows/win32/winauto/microsoft-active-accessibility">Microsoft Active Accessibility</a> [[MSAA]], <a href="https://docs.microsoft.com/en-us/windows/win32/winauto/entry-uiauto-win32">Microsoft User Interface Automation</a> [[UI-AUTOMATION]], <abbr title="Microsoft Active Accessibility">MSAA</abbr> with <cite><a href="https://docs.microsoft.com/en-us/windows/win32/winauto/iaccessibleex"><abbr title="User Interface Automation">UIA</abbr> Express</a></cite> [[UIA-EXPRESS]], the
      	<a href="https://developer.apple.com/documentation/appkit/nsaccessibility">Mac <abbr title="OS Ten">OS X</abbr> Accessibility Protocol</a> [[AXAPI]], the <cite><a href="https://developer.gnome.org/atk/unstable/">Linux/Unix Accessibility Toolkit</a></cite> [[ATK]] and <cite><a href="https://developer.gnome.org/libatspi/stable/">Assistive Technology Service Provider Interface</a></cite> [[AT-SPI]], and <a href="https://wiki.linuxfoundation.org/accessibility/iaccessible2/start">IAccessible2</a> [[IAccessible2]].</p>
    </dd>
    <dt><dfn>Accessibility Subtree</dfn></dt>
    <dd>
      <p>An <a>accessible object</a> in the <a>accessibility tree</a> and its descendants in that tree. It does not include objects which have relationships other than parent-child in that tree. For example, it does not include objects linked via <pref>aria-flowto</pref> unless those objects are also descendants in the <a>accessibility tree</a>.</p>
    </dd>
    <dt><dfn>Accessibility Tree</dfn></dt>
    <dd>
      <p>Tree of <a class="termref" data-lt="accessible object">accessible objects</a> that represents the structure of the user interface (UI). Each node in the accessibility tree represents an element in the <abbr title="user interface">UI</abbr> as exposed through the <a>accessibility <abbr title="Application Programming Interface">API</abbr></a>; for example, a push button, a check box, or container.</p>
    </dd>
    <dt><dfn>Accessible Description</dfn></dt>
    <dd>
      <p>An accessible description provides additional information, related to an interface element, that complements the <a>accessible name</a>. The accessible description might or might not be visually perceivable. </p>
    </dd>
	<dt><dfn data-lt="accessible name|accessible names">Accessible Name</dfn></dt>
    <dd>
      <p>The accessible name is the name of a user interface element. Each platform <a>accessibility <abbr title="application programming interface">API</abbr></a> provides the accessible name property. The value of the accessible name may be derived from a visible (e.g., the visible text on a button) or invisible (e.g., the text alternative that describes an icon) property of the user interface element.  See related <a>accessible description</a>.</p>
      <p>A simple use for the accessible name property may be illustrated by an &quot;OK&quot; button. The text &quot;OK&quot; is the accessible name. When the button receives focus, assistive technologies may concatenate the platform's role description with the accessible name. For example, a screen reader may speak &quot;push-button OK&quot; or &quot;OK button&quot;. The order of concatenation and specifics of the role description (e.g., &quot;button&quot;, &quot;push-button&quot;, &quot;clickable button&quot;) are determined by platform <a class="termref" data-lt="accessibility api">accessibility API</a>s or <a>assistive technologies</a>.</p>
    </dd>
	<dt><dfn data-lt="accessible object|accessible objects">Accessible object</dfn></dt>
    <dd>
      <p>A <a>node</a> in the <a>accessibility tree</a> of a platform <a>accessibility <abbr title="application programming interface">API</abbr></a>. Accessible objects expose various <a class="termref" data-lt="state">states</a>, <a class="termref" data-lt="property">properties</a>, and <a class="termref" data-lt="event">events</a> for use by <a>assistive technologies</a>.  In the context of markup languages (e.g., HTML and SVG) in general, and of WAI-ARIA in particular, markup <a class="termref" data-lt="element">elements</a> and their <a class="termref" data-lt="attribute">attributes</a> are represented as accessible objects.  </p>
    </dd>
    <dt><dfn>Activation behavior</dfn></dt>
    <dd>
      <p>The action taken when an <a>event</a>, typically initiated by users through an input device, causes an element to fulfill a defined role. The role may be defined for that element by the host language, or by author-defined variables, or both. The role for any given element may be a generic action, or may be unique to that element. For example, the activation behavior of an <abbr title="Hypertext Markup Language">HTML</abbr> or <abbr title="Scalable Vector Graphics">SVG</abbr> <code>&lt;a&gt;</code> element shall be to cause the user agent to traverse the link specified in the <code>href</code> attribute, with the further optional parameter of specifying the browsing context for the traversal (such as the current window or tab, a named window, or a new window); the activation behavior of an <abbr title="Hypertext Markup Language">HTML</abbr> <code>&lt;input&gt;</code> element with the <code>type</code> attribute value <code>submit</code> shall be to send the values of the form elements to an author-defined <abbr title="Internationalized Resource Identifiers">IRI</abbr> by the author-defined <abbr title="Hypertext Transfer Protocol">HTTP</abbr> method.</p>
    </dd>
    <dt><dfn data-lt="assistive technologies|assistive technology">Assistive Technologies</dfn></dt>
    <dd><p>Hardware and/or software that:</p>
			<ul>
				<li>relies on services provided by a <a>user agent</a> to retrieve and render Web content </li>
				<li>works with a user agent or web content itself through the use of APIs, and</li>
				<li>provides services beyond those offered by the user agent to facilitate user interaction with web content by people with disabilities</li>
			</ul>
      <p>This definition may differ from that used in other documents.</p>
    <p>Examples of assistive technologies that are important in the context
      of this document include the following:</p>
    <ul>
      <li>screen magnifiers, which are used to enlarge and improve the visual readability of rendered text and images;</li>
      <li>screen readers, which are most-often used to convey information through synthesized speech or a refreshable Braille display;</li>
      <li>text-to-speech software, which is used to convert text into synthetic speech;</li>
      <li>speech recognition software, which is used to allow spoken control and dictation;</li>
      <li>alternate input technologies (including head pointers, on-screen keyboards, single switches, and sip/puff devices), which are used to simulate the keyboard;</li>
      <li>alternate pointing devices, which are used to simulate mouse pointing and clicking.</li>
    </ul>
    </dd>
    <dt><dfn data-lt="attribute|attributes">Attribute</dfn></dt>
    <dd>
      <p>In this specification, attribute is used as it is in markup languages. Attributes are structural features added to <a class="termref" href="#dfn-element">elements</a> to provide information about the <a class="termref" href="#dfn-state">states</a> and <a class="termref" href="#dfn-property">properties</a> of the <a class="termref" href="#dfn-object">object</a> represented by the element.</p>
    </dd>
    <dt><dfn data-lt="class|classes">Class</dfn></dt>
    <dd>
      <p>A set of instance <a class="termref" href="#dfn-object">objects</a> that share similar characteristics.</p>
    </dd>
    <dt><dfn data-lt="deprecated|deprecate|deprecation">Deprecated</dfn></dt>
    <dd>
      <p>A deprecated <a class="termref" href="#dfn-role">role</a>, <a class="termref" href="#dfn-state">state</a>, or <a class="termref" href="#dfn-property">property</a> is one which has been outdated by newer constructs or changed circumstances, and which may be removed in future versions of the <abbr title="Accessible Rich Internet Applications">WAI-ARIA</abbr> specification. <a class="termref" data-lt="user agent">User agents</a> are encouraged to continue to support items identified as deprecated for backward compatibility. For more information, see <a href="#deprecated" class="specref">Deprecated Requirements</a> in the Conformance section.</p>
    </dd>
    <dt><dfn data-lt="desktop focus|desktop focus events">Desktop focus event</dfn></dt>
    <dd>
      <p>Event from/to the host operating system via the accessibility <abbr title="application programming interface">API</abbr>, notifying of a change of input focus.</p>
    </dd>
	<dt><dfn>DOMString</dfn>
	<dd>Sequence of 16-bit unsigned integers, typically interpreted as UTF-16 code units. This corresponds to the JavaScript primitive String type.</dd>
    <dt><dfn data-lt="element|elements|element's">Element</dfn></dt>
    <dd>
      <p>In this specification, element is used as it is in markup languages. Elements are the structural elements in markup language that contains the data profile for <a class="termref" data-lt="object">objects</a>.</p>
    </dd>
    <dt><dfn data-lt="event|events">Event</dfn></dt>
    <dd>
      <p>A programmatic message used to communicate discrete changes in the <a>state</a> of an <a>object</a> to other objects in a computational system. User input to a web page is commonly mediated through abstract events that describe the interaction and can provide notice of changes to the state of a document object. In some programming languages, events are more commonly known as notifications.</p>
    </dd>
    <dt><dfn>Expose</dfn></dt>
    <dd>
      <p>Translated to platform-specific <a class="termref" data-lt="accessibility api">accessibility APIs</a> as defined in the <a href="" class="core-mapping">Core Accessibility API Mappings</a>.</p>
    </dd>
	<dt><dfn data-lt="graphical document|graphical documents">Graphical Document</dfn></dt>
    <dd>
      <p>A document containing graphic representations with user-navigable parts. Charts, maps, diagrams, blueprints, and dashboards are examples of graphical documents. A graphical document is composed using any combination of symbols, images, text, and graphic primitives (shapes such as circles, points, lines, paths, rectangles, etc).</p>
    </dd>
    <dt><dfn>Hidden</dfn></dt>
    <dd>
        <p>Indicates that the <a>element</a> is not visible, <a>perceivable</a>, or interactive to <em>any</em> user. An element is considered <em>hidden</em> if it or any one of its ancestor elements is not rendered or is explicitly hidden.</p>
    </dd>
    <dt><dfn data-lt="informative|non-normative">Informative</dfn></dt>
    <dd>
      <p>Content provided for information purposes and not required for conformance. Content required for conformance is referred to as <a>normative</a>.</p>
    </dd>
    <dt><dfn>Keyboard Accessible</dfn></dt>
    <dd>
    	<p>Accessible to the user using a keyboard or <a>assistive technologies</a> that mimic keyboard input, such as a sip and puff tube. References in this document relate to <cite><a href="https://www.w3.org/TR/WCAG21/#keyboard-accessible"><abbr title="Web Content Accessibility Guidelines">WCAG</abbr> 2.1 Guideline 2.1: Make all functionality available from a keyboard</a></cite> [[WCAG21]].</p>
    </dd>
    <dt><dfn data-lt="landmark|landmarks">Landmark</dfn></dt>
    <dd>
      <p>A type of region on a page to which the user may want quick access. Content in such a region is different from that of other regions on the page and relevant to a specific user purpose, such as navigating, searching, perusing the primary content, etc.</p>
    </dd>
    <dt><dfn data-lt="live region|live regions">Live Region</dfn></dt>
    <dd>
      <p>Live regions are perceivable regions of a web page that are typically updated as a result of an external event when user focus may be elsewhere. These regions are not always updated as a result of a user interaction. Examples of live regions include a chat log, stock ticker, or a sport scoring section that updates periodically to reflect game statistics. Since these asynchronous areas are expected to update outside the user's area of focus, assistive technologies such as screen readers have either been unaware of their existence or unable to process them for the user. WAI-ARIA has provided a collection of properties that allow the author to identify these live regions and process them: aria-live, aria-relevant, aria-atomic, and aria-busy.</p>
    </dd>
    <dt><dfn>Primary Content Element</dfn></dt>
    <dd>
      <p>An implementing host language's primary content element, such as the <code>body</code> element in HTML.</p>
    </dd>
    <dt><dfn data-lt="managed state|managed states">Managed State</dfn></dt>
    <dd>
      <p><a>Accessibility API</a> <a>state</a> that is controlled by the user agent, such as focus and selection. These are contrasted with &quot;unmanaged states&quot; that are typically controlled by the author. Nevertheless, authors can override some managed states, such as aria-posinset and aria-setsize. Many managed states have corresponding CSS pseudo-classes, such as :focus, and pseudo-elements, such as ::selection, that are also updated by the user agent.</p>
    </dd>
    <dt><dfn>Nemeth Braille</dfn></dt>
    <dd>
        <p>The Nemeth Braille Code for Mathematics is a braille code for encoding mathematical and scientific notation. See <cite><a href="https://en.wikipedia.org/wiki/Nemeth_Braille">Nemeth Braille on Wikipedia</a>.</cite></p>
    </dd>
    <dt><dfn>Node</dfn></dt>
    <dd>
      <p>Basic type of <a class="termref">object</a> in the <abbr title="Document Object Model">DOM</abbr> tree or <a class="termref">accessibility tree</a>. <abbr title="Document Object Model">DOM</abbr> nodes are further specified as <a class="termref">Element</a> or <a class="termref" data-lt="Text node">Text nodes</a>, among other types. The nodes of an <a class="termref">accessibility tree</a> are <a class="termref" data-lt="accessible object">accessible objects</a>.  </p>
    </dd>
    <dt><dfn>Normative</dfn></dt>
    <dd>
      <p>Required for conformance. By contrast, content identified as <a>informative</a> or &quot;non-normative&quot; is not required for conformance.</p>
    </dd>
    <dt><dfn data-lt="object|objects">Object</dfn></dt>
    <dd>
      <p>In the context of user interfaces,  an item in the   perceptual user experience, represented in markup languages by one or   more <a class="termref" data-lt="element">elements</a>, and rendered by <a class="termref" data-lt="user agent">user agents</a>.</p>
    In the context of programming, the instantiation of one or more <a class="termref" data-lt="class">classes</a> and interfaces which define the general characteristics of similar objects. An object in an <a>accessibility <abbr title="Application Programming Interfaces">API</abbr></a> may represent one or more DOM objects. <a class="termref" data-lt="accessibility api">Accessibility APIs</a> have defined interfaces that are distinct from DOM interfaces.</dd>
  
    <dt><dfn>Ontology</dfn></dt>
    <dd>
      <p>A description of the characteristics of <a class="termref" data-lt="class">classes</a> and how they relate to each other.</p>
    </dd>
    <dt><dfn>Operable</dfn></dt>
    <dd>
      <p>Usable by users in ways they can control. References in this document relate to <cite><a href="https://www.w3.org/TR/WCAG21/#operable"><abbr title="Web Content Accessibility Guidelines">WCAG</abbr> 2.1 Principle 2: Content must be operable</a></cite> [[WCAG21]]. See <a>Keyboard Accessible</a>.</p>
    </dd>
    <dt><dfn data-lt="owned element|owned|owned element's|owned elements">Owned Element</dfn></dt>
    <dd>
      <p>An 'owned element' is any <abbr title="Document Object Model">DOM</abbr> descendant of the <a>element</a>, any element specified as a child via <pref>aria-owns</pref>, or any <abbr title="Document Object Model">DOM</abbr> descendant of the owned child.</p>
    </dd>
    <dt><dfn data-lt="owning element|owning">Owning Element</dfn></dt>
    <dd>
      <p>An 'owning element' is any <abbr title="Document Object Model">DOM</abbr> ancestor of the <a>element</a>, or any element with an <pref>aria-owns</pref> attribute which references the ID of the   element. </p>
    </dd>
    <dt><dfn>Perceivable</dfn></dt>
    <dd>
      <p>Presentable to users in ways they can sense. References in this document relate to <cite><a href="https://www.w3.org/TR/WCAG21/#perceivable"><abbr title="Web Content Accessibility Guidelines">WCAG</abbr> 2.1 Principle 1: Content must be perceivable</a></cite> [[WCAG21]].</p>
    </dd>
    <dt><dfn data-lt="property|properties">Property</dfn></dt>
    <dd>
      <p><a class="termref" data-lt="attribute">Attributes</a> that are essential to the nature of a given <a>object</a>, or that represent a data value associated with the object. A change of a property may significantly impact the meaning or presentation of an object. Certain properties (for example, <pref>aria-multiline</pref>) are less likely to change than <a class="termref" href="#dfn-state">states</a>, but note that the frequency of change difference is not a rule. A few properties, such as <pref>aria-activedescendant</pref>, <pref>aria-valuenow</pref>, and <pref>aria-valuetext</pref> are expected to change often. See <a class="specref" href="#statevsprop">clarification of states versus properties</a>.</p>
    </dd>
    <dt><dfn data-lt="relationship|relationships">Relationship</dfn></dt>
    <dd>
      <p>A connection between two distinct things. Relationships may be of various types to indicate which <a>object</a> labels another, controls another, etc.</p>
    </dd>
    <dt><dfn data-lt="role|roles">Role</dfn></dt>
    <dd>
      <p>Main indicator of type. <!-- (removing, vague) The object's role is the class of <a class="termref" data-lt="object">objects</a> of which it is a member. --> This <a class="termref" data-lt="semantics">semantic</a> association allows tools to present and support interaction with the object in a manner that is consistent with user expectations about other objects of that type.</p>
    </dd>
    <dt><dfn>Root <abbr title="Accessible Rich Internet Application">WAI-ARIA</abbr> node</dfn></dt>
    <dd>
      <p> The primary element containing non-metadata content. In many languages, this is  the document element but in <abbr title="Hypertext Markup Language">HTML</abbr>, it is the <code>&lt;body&gt;</code>.</p>
    </dd>
    <dt><dfn data-lt="semantics|semantic|semantically">Semantics</dfn></dt>
    <dd>
      <p>The meaning of something as understood by a human, defined in a way that computers can process a representation of an <a>object</a>, such as <a class="termref" data-lt="element">elements</a> and <a class="termref" data-lt="attribute">attributes</a>, and reliably represent the object in a way that various humans will achieve a mutually consistent understanding of the object.</p>
    </dd>
    <dt><dfn data-lt="state|states">State</dfn></dt>
    <dd>
      <p>A state is a dynamic <a class="termref" href="#dfn-property">property</a> expressing characteristics of an <a>object</a> that may change in response to user action or automated processes. States do not affect the essential nature of the object, but represent data associated with the object or user interaction possibilities. See <a class="specref" href="#statevsprop">clarification of states versus properties</a>.</p>
    </dd>
    <dt><dfn>Sub-document</dfn></dt>
    <dd>
      <p>Any document created from a <code>&lt;frame&gt;</code>, <code>&lt;iframe&gt;</code> or similar mechanism. A sub-document may contain a document, an application or any widget such as a calendar pulled in from another server. In the <a>accessibility tree</a> there are two <a class="termref" data-lt="accessible object">accessible objects</a> for this situation&mdash;one represents the <code>&lt;frame&gt;</code>/<code>&lt;iframe&gt;</code> element in the parent document, which parents a single <a>accessible object</a> child representing the spawned document contents.</p>
    </dd>
    <dt><dfn>Target Element</dfn></dt>
    <dd>
      <p>An element specified in a <abbr title="Accessible Rich Internet Application">WAI-ARIA</abbr> relation. For example, in <code> &lt;div aria-controls=”elem1”&gt;</code>, where <code>“elem1”</code> is the ID for the target element.</p>
    </dd>
    <dt><dfn>Taxonomy</dfn></dt>
    <dd>
      <p>A hierarchical definition of how the characteristics of various <a class="termref" data-lt="class">classes</a> relate to each other, in which classes inherit the properties of superclasses in the hierarchy. A taxonomy can comprise part of the formal definition of an <a>ontology</a>.</p>
    </dd>
    <dt><dfn>Text node</dfn></dt>
    <dd>
      <p>Type of <abbr title="Document Object Model">DOM</abbr> <a class="termref" data-lt="node">node</a> that represents the textual content of an <a class="termref">attribute</a> or an <a class="termref">element</a>. A Text node has no child nodes.  </p>
    </dd>
    <dt><dfn>Tooltip attribute</dfn></dt>
    <dd>
      <p>Any host language attribute that would result in a user agent generating a tooltip such as in response to a mouse hover in desktop user agents.</p>
    </dd>
    <dt><dfn>Understandable</dfn></dt>
    <dd>
      <p>Presentable to users in ways they can construct an appropriate meaning. References in this document relate to <cite><a href="https://www.w3.org/TR/WCAG21/#understandable"><abbr title="Web Content Accessibility Guidelines">WCAG</abbr> 2.1 Principle 3: Information and the operation of user interface must be understandable</a></cite> [[WCAG21]].</p>
    </dd>
	<dt><dfn data-lt="unicode braille">Unicode Braille Patterns</dfn></dt>
	<dd>
		<p>In Unicode, braille is represented in a block called Braille Patterns (U+2800..U+28FF). The block contains all 256 possible patterns of an 8-dot braille cell; this includes the complete 6-dot cell range which is represented by U+2800..U+283F. In all braille systems, the braille pattern dots-0 (U+2800) is used to represent a space or the lack of content; it is also called a blank Braille pattern. See <cite><a href="https://en.wikipedia.org/wiki/Braille_Patterns">Braille Patterns on Wikipedia</a>.</cite></p>
	</dd>
	<dt><dfn data-lt="user agent|user agents">User Agent</dfn></dt>
    <dd>
      <p>Any software that retrieves, renders and facilitates end user interaction with Web content. This definition may differ from that used in other documents.</p>
    </dd>
    <dt><dfn>Valid IDREF</dfn></dt>
    <dd>
      <p>A reference to a target element in the same document that has a matching ID</p>
    </dd>
    <dt><dfn data-lt="widget|widgets">Widget</dfn></dt>
    <dd>
      <p>Discrete user interface <a class="termref" href="#dfn-object">object</a> with which the user can interact. Widgets range from simple objects that have one value or operation (e.g., check boxes and menu items), to complex objects that contain many managed sub-objects (e.g., trees and grids).</p>
    </dd>
  </dl>