diff --git a/source b/source
index eb7730afdb1..fad03791fb3 100644
--- a/source
+++ b/source
@@ -84410,8 +84410,10 @@ interface <dfn interface>BarProp</dfn> {
 
    <li><p>Set <var>settings object</var>'s <span data-x="concept-environment-creation-url">creation
    URL</span> to <var>creationURL</var>, <var>settings object</var>'s <span>top-level creation
-   URL</span> to <var>topLevelCreationURL</var>, and <var>settings object</var>'s <span>top-level
-   origin</span> to <var>topLevelOrigin</var>.</p></li>
+   URL</span> to <var>topLevelCreationURL</var>, <var>settings object</var>'s <span>top-level
+   origin</span> to <var>topLevelOrigin</var>, and <var>settings object</var>'s <span>top-level
+   site</span> to the result of <span data-x="obtain a site">obtaining a site</span> given
+   <var>topLevelOrigin</var>.</p></li>
 
    <li><p>Set <var>realm</var>'s [[HostDefined]] field to <var>settings object</var>.</p></li>
   </ol>
@@ -89837,8 +89839,9 @@ interface <dfn interface>Location</dfn> { // but see also <a href="#the-location
         data-x="concept-environment-target-browsing-context">target browsing context</span> is
         <var>browsingContext</var>, <span data-x="concept-environment-creation-url">creation
         URL</span> is <var>currentURL</var>, <span>top-level creation URL</span> is
-        <var>topLevelCreationURL</var>, and <span>top-level origin</span> is
-        <var>topLevelOrigin</var>.</p>
+        <var>topLevelCreationURL</var>, <span>top-level origin</span> is
+        <var>topLevelOrigin</var>, and <span>top-level site</span> is the result of <span
+        data-x="obtain a site">obtaining a site</span> given <var>topLevelOrigin</var>.</p>
 
         <p class="note">The created environment's <span
         data-x="concept-environment-active-service-worker">active service worker</span> is set in
@@ -92834,6 +92837,16 @@ interface <dfn interface>BeforeUnloadEvent</dfn> : <span>Event</span> {
     involved.</p>
    </dd>
 
+   <dt>A <dfn id="concept-environment-top-level-site" export
+   for="environment">top-level site</dfn></dt>
+   <dd><p>A <span>site</span> <span data-x="obtain a site">obtained</span> from the "top-level"
+   <span>environment settings object</span>'s
+   <span data-x="concept-settings-object-origin">origin</span>.  For a "top-level" potential
+   execution environment it is set to the site of the
+   <span data-x="concept-environment-creation-url">creation url</span>.  For a worker it is set to
+   the top-level site of its creator.</p>
+   </dd>
+
    <dt>A <dfn data-x="concept-environment-target-browsing-context" export
    for="environment">target browsing context</dfn></dt>
    <dd><p>Null or a target <span>browsing context</span> for a <span
@@ -105004,7 +105017,8 @@ interface <dfn interface>SharedWorkerGlobalScope</dfn> : <span>WorkerGlobalScope
    <li><p>Set <var>settings object</var>'s <span data-x="concept-environment-id">id</span> to a new
    unique opaque string, <span data-x="concept-environment-creation-url">creation URL</span> to
    <var>worker global scope</var>'s <span>url</span>, <span>top-level creation URL</span> to null,
-   <span data-x="concept-environment-target-browsing-context">target browsing context</span> to
+   <span>top-level site</span> to <var>outside settings</var>'s <span>top-level site</span>, <span
+   data-x="concept-environment-target-browsing-context">target browsing context</span> to
    null, and <span data-x="concept-environment-active-service-worker">active service worker</span>
    to null.</p></li>