diff --git a/‎index.html‎
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@@ -309,7 +309,12 @@ <h1>Important Terms</h1>
 			</dd>
 			<dt><dfn data-dfn-for="element" data-export="">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>
+			  <p>Indicates that the <a>element</a> is excluded from the accessibility tree and therefore not exposed to accessibility APIs.<p>
+			  <p>Related: <a href="#tree_exclusion">Excluding Elements in the Accessibility Tree</a>, [=element/hidden from all users=], <sref>aria-hidden</sref>.<p>
+			<dt><dfn data-dfn-for="element" data-lt="hide from all users" data-export="">Hidden From All Users</dfn></dt>
+			<dd>
+			  <p>Indicates that the <a>element</a> is not visible, <a>perceivable</a>, or interactive to <em>any</em> user. Note that an <a>element</a> can be [=element/hidden=] but not [=element/hidden from all users=] by using <code>aria-hidden</code>.</p>
+			  <p>Related: <a href="#tree_exclusion">Excluding Elements in the Accessibility Tree</a>, [=element/hidden=], <sref>aria-hidden</sref>.<p>
 			</dd>
 			<dt><dfn>Identifies</dfn></dt>
 			<dd>
@@ -8675,7 +8680,7 @@ <h5>Presentational Role Inheritance</h5>
 				<p>Authors MUST ensure [=elements=] with <a>role</a> <rref>tab</rref> are contained in, or [=ARIA/owned=] by, an element with the role <rref>tablist</rref>.</p>
 				<p>Authors SHOULD ensure the <rref>tabpanel</rref> associated with the currently active tab is <a>perceivable</a> to the user.</p>
 				<!-- keep following para synced with its counterpart in #tablist -->
-				<p>For a single-selectable <rref>tablist</rref>, authors SHOULD hide other <code>tabpanel</code> [=elements=] from the user until the user selects the tab associated with that tabpanel. For a multi-selectable <rref>tablist</rref>, authors SHOULD ensure that the <rref>tab</rref> for each visible <rref>tabpanel</rref> has the <sref>aria-expanded</sref> <a>attribute</a> set to <code>true</code>, and that the <code>tabs</code> associated with the remaining hidden <code>tabpanel</code> elements have their <sref>aria-expanded</sref> attributes set to <code>false</code>.</p>
+				<p>For a single-selectable <rref>tablist</rref>, authors SHOULD [=element/hide from all users=] other <code>tabpanel</code> [=elements=] until the user selects the tab associated with that tabpanel. For a multi-selectable <rref>tablist</rref>, authors SHOULD ensure that the <rref>tab</rref> for each visible <rref>tabpanel</rref> has the <sref>aria-expanded</sref> <a>attribute</a> set to <code>true</code>, and that the <code>tabs</code> associated with the remaining [=element/hidden from all users=] <code>tabpanel</code> elements have their <sref>aria-expanded</sref> attributes set to <code>false</code>.</p>
 				<p>Authors SHOULD ensure that a selected tab has its <sref>aria-selected</sref> attribute set to <code>true</code>, that inactive tab elements have their <sref>aria-selected</sref> attribute set to <code>false</code>, and that the currently selected tab provides a visual indication that it is selected.</p>
         <p>In certain conditions, a user agent MAY provide an implicit value for <sref>aria-selected</sref> for each <rref>tab</rref> in a <rref>tablist</rref>, and if it does, the user agent MUST ensure the following conditions are met before providing an implicit value:</p>
         <ul>
@@ -8874,7 +8879,7 @@ <h5>Presentational Role Inheritance</h5>
 				<p>To be <a>keyboard accessible</a>, authors SHOULD manage focus of descendants for all instances of this <a>role</a>, as described in <a href="#managingfocus">Managing Focus</a>.</p>
 
 				<!-- keep following para synced with its counterpart in #tab -->
-				<p>For a single-selectable <rref>tablist</rref>, authors SHOULD hide other <code>tabpanel</code> [=elements=] from the user until the user selects the tab associated with that tabpanel. For a multi-selectable <rref>tablist</rref>, authors SHOULD ensure that the <rref>tab</rref> for each visible <rref>tabpanel</rref> has the <sref>aria-expanded</sref> <a>attribute</a> set to <code>true</code>, and that the <code>tabs</code> associated with the remaining hidden <code>tabpanel</code> elements have their <sref>aria-expanded</sref> attributes set to <code>false</code>.</p>
+				<p>For a single-selectable <rref>tablist</rref>, authors SHOULD [=element/hide from all users=] other <code>tabpanel</code> [=elements=] until the user selects the tab associated with that tabpanel. For a multi-selectable <rref>tablist</rref>, authors SHOULD ensure that the <rref>tab</rref> for each visible <rref>tabpanel</rref> has the <sref>aria-expanded</sref> <a>attribute</a> set to <code>true</code>, and that the <code>tabs</code> associated with the remaining [=element/hidden from all users=] <code>tabpanel</code> elements have their <sref>aria-expanded</sref> attributes set to <code>false</code>.</p>
 
 				<!-- keep following para synced with its counterpart in #tabpanel -->
 				<p><rref>tablist</rref> elements are typically placed near usually preceding, a series of <rref>tabpanel</rref> elements. See the <cite><a href="" class="practices"><abbr title="Accessible Rich Internet Applications">WAI-ARIA</abbr> Authoring Practices</a></cite> for details on implementing a tab set design pattern.</p>
@@ -11479,8 +11484,8 @@ <h2>Definitions of States and Properties (all aria-* attributes)</h2>
 				<p><a>Identifies</a> the <a>element</a> (or elements) that provides an error message for an <a>object</a>. See related <sref>aria-invalid</sref> and <pref>aria-describedby</pref>.</p>
 				<p>The <code>aria-errormessage</code> attribute references other elements that contain error message text. Authors MUST use <sref>aria-invalid</sref> in conjunction with <code>aria-errormessage</code>.</p>
 				<p>When the value of an object is not valid, <sref>aria-invalid</sref> is set to <code>true</code>, which indicates that the message contained by elements referenced by <code>aria-errormessage</code> is pertinent.</p>
-				<p>When an object is in a valid state, it has either <sref>aria-invalid</sref> set to <code>false</code> or it does not have the <sref>aria-invalid</sref> attribute. Authors MAY use <code>aria-errormessage</code> on an object that is currently valid, but only if the elements referenced by <code>aria-errormessage</code> are [=element/hidden=], because the message they contain is not pertinent.</p>
-				<p>When <code>aria-errormessage</code> is pertinent, authors MUST ensure the content is not hidden so users can navigate to and examine the error message. Similarly, when <code>aria-errormessage</code> is not pertinent, authors MUST either ensure the content is [=element/hidden=] or remove the <code>aria-errormessage</code> attribute or its value.</p>
+				<p>When an object is in a valid state, it has either <sref>aria-invalid</sref> set to <code>false</code> or it does not have the <sref>aria-invalid</sref> attribute. Authors MAY use <code>aria-errormessage</code> on an object that is currently valid, but only if the elements referenced by <code>aria-errormessage</code> are [=element/hidden from all users=], because the message they contain is not pertinent.</p>
+				<p>When <code>aria-errormessage</code> is pertinent, authors MUST ensure the content is not [=element/hidden from all users=] so users can navigate to and examine the error message. Similarly, when <code>aria-errormessage</code> is not pertinent, authors MUST either ensure the content is [=element/hidden from all users=] or remove the <code>aria-errormessage</code> attribute or its value.</p>
 				<p>User agents MUST NOT expose <code>aria-errormessage</code> for an object with an <sref>aria-invalid</sref> value of <code>false</code>.</p>
 				<p>Authors MAY call attention to a newly rendered error message with a live region by either applying an <pref>aria-live</pref> property or using one of the <a href="#live_region_roles">live region roles</a>, such as <rref>alert</rref>. A live region is appropriate when an error message is displayed to users after they have provided an invalid value.</p>
 				<p>A typical message describes what is wrong and informs users what is required. For example, an error message might be, <q>Invalid time: the time must be between 9:00 AM and 5:00 PM.</q> The following example code shows markup for an initial valid state and for a subsequent invalid state. Note the changes to <sref>aria-invalid</sref> on the text input <a>object</a>, and to <pref>aria-live</pref> on the <a>element</a> containing the text of the error message:</p>
@@ -11812,11 +11817,11 @@ <h2>Definitions of States and Properties (all aria-* attributes)</h2>
 					</tr>
 					<tr>
 						<th class="value-name" scope="row">true</th>
-						<td class="value-description">The element is hidden from the accessibility API.</td>
+						<td class="value-description">The element is [=element/hidden=] from the accessibility API.</td>
 					</tr>
 					<tr>
 						<th class="value-name" scope="row"><strong class="default">undefined (default)</strong></th>
-						<td class="value-description">The element's hidden state is determined by the user agent based on whether it is rendered.</td>
+						<td class="value-description">The element's [=element/hidden=] state is determined by the user agent based on whether it is rendered.</td>
 					</tr>
 				</tbody>
 			</table>
@@ -13360,7 +13365,7 @@ <h2>Excluding Elements from the Accessibility Tree</h2>
 	</section>
 	<section id="tree_inclusion">
 	  <h2>Including Elements in the Accessibility Tree</h2>
-          <p>If not excluded from or marked as hidden in the accessibility tree per the rules above in <a href="#tree_exclusion">Excluding Elements in the Accessibility Tree</a>, user agents MUST provide an <a>accessible object</a> in the <a class="termref">accessibility tree</a> for <abbr title="Document Object Model">DOM</abbr> [=elements=] that meet any of the following criteria:</p>
+          <p>If not excluded from the accessibility tree per the rules above in <a href="#tree_exclusion">Excluding Elements in the Accessibility Tree</a>, user agents MUST provide an <a>accessible object</a> in the <a class="termref">accessibility tree</a> for <abbr title="Document Object Model">DOM</abbr> [=elements=] that meet any of the following criteria:</p>
           <ul>
             <li>Elements that are not [=element/hidden=] and may fire an <a>accessibility <abbr title="Application Program Interface">API</abbr></a> <a>event</a>, including:
               <ul>
@@ -13370,7 +13375,7 @@ <h2>Including Elements in the Accessibility Tree</h2>
 	        </li>
             <li>Elements that have an explicit role or a global <abbr title="Accessible Rich Internet Application">WAI-ARIA</abbr> attribute and do not have <sref>aria-hidden</sref> set to <code>true</code>. (See <a href="#tree_exclusion">Excluding Elements in the Accessibility Tree</a> for additional guidance on <sref>aria-hidden</sref>.)</li>
             <li>Elements that are not [=element/hidden=] and have an ID that is referenced by another element via a <abbr title="Accessible Rich Internet Application">WAI-ARIA</abbr> property.
-            <p class="note">Text equivalents for hidden referenced objects may still be used in the <a href="#mapping_additional_nd" class="accname">name and description computation</a> even when not included in the accessibility tree.</p>
+            <p class="note">Text equivalents for [=element/hidden=] referenced objects may still be used in the <a href="#mapping_additional_nd" class="accname">name and description computation</a> even when not included in the accessibility tree.</p>
             </li>
           </ul>
 	</section>