diff --git a/Gemfile.lock b/Gemfile.lock
index f8b7428c..3cea9e32 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,6 +1,6 @@
 GIT
   remote: git://github.com/ruby-rdf/json-ld.git
-  revision: afe7b3b10547b552676d1379a2be4bc34cf83d02
+  revision: 6bb0c2d269e8cf80152d519ee5fd16696812b1f2
   branch: develop
   specs:
     json-ld (3.0.2)
@@ -12,7 +12,7 @@ GIT
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.2)
+    addressable (2.6.0)
       public_suffix (>= 2.0.2, < 4.0)
     bcp47 (0.3.3)
       i18n
@@ -31,7 +31,7 @@ GEM
     hamster (3.0.0)
       concurrent-ruby (~> 1.0)
     htmlentities (4.3.4)
-    i18n (1.5.1)
+    i18n (1.5.3)
       concurrent-ruby (~> 1.0)
     json-ld-preloaded (3.0.2)
       json-ld (~> 3.0)
@@ -73,14 +73,14 @@ GEM
     multi_json (1.13.1)
     net-http-persistent (3.0.0)
       connection_pool (~> 2.2)
-    nokogiri (1.10.0)
+    nokogiri (1.10.1)
       mini_portile2 (~> 2.4.0)
     nokogumbo (1.5.0)
       nokogiri
     public_suffix (3.0.3)
     rack (2.0.6)
     rake (12.3.2)
-    rdf (3.0.9)
+    rdf (3.0.10)
       hamster (~> 3.0)
       link_header (~> 0.0, >= 0.0.8)
     rdf-aggregate-repo (2.2.1)
@@ -126,7 +126,7 @@ GEM
       rdf-turtle (~> 3.0, >= 3.0.3)
     rdf-trix (2.2.1)
       rdf (>= 2.2, < 4.0)
-    rdf-turtle (3.0.3)
+    rdf-turtle (3.0.5)
       ebnf (~> 1.1)
       rdf (~> 3.0)
     rdf-vocab (3.0.4)
diff --git a/index.html b/index.html
index 2e11227d..7e882506 100644
--- a/index.html
+++ b/index.html
@@ -49,8 +49,14 @@
           company:    "Spec-Ops",
           companyURL: "https://spec-ops.io/",
           w3cid:      "44770",
-          note:       "v1.0 and v1.1" }
-        ],
+          note:       "v1.0 and v1.1" },
+        { name:       "Pierre-Antoine Champin",
+          url:        "http://champin.net/",
+          company:    "LIRIS - Université de Lyon",
+          companyURL: "https://liris.cnrs.fr/",
+          w3cid:      "42931",
+          note:       "v1.1" }
+      ],
 
       // editors, add as many as you like
       // only "name" is required
@@ -3104,6 +3110,295 @@ <h3>Using the Document Base for the Default Vocabulary</h3>
   <p class="note">Scoped Contexts are a new feature in JSON-LD 1.1, requiring
     <a>processing mode</a> set to <code>json-ld-1.1</code>.</p>
 </section>
+
+<section class="informative changed"><h2>Sealed Term Definitions</h2>
+  <p>JSON-LD is used in many specifications as the specified data format.
+    However, there is also a desire to allow some JSON-LD contents to be processed as plain JSON,
+    without using any of the JSON-LD algorithms.
+    Because JSON-LD is very flexible,
+    some terms from the original format may be locally overridden
+    through the use of embedded contexts,
+    and take a different meaning for JSON-LD based implementations.
+    On the other hand, "plain JSON" implementations may not be able to interpret these embedded contexts,
+    and hence will still interpret those terms with their original meaning.
+    To prevent this divergence of interpretation,
+    JSON-LD 1.1 allows term definitions to be <em>sealed</em>.
+    </p>
+  <p>A <dfn>sealed term definition</dfn> is a term definition with a member <code>@sealed</code> set to <code>true</code>.
+    It prevents further contexts to override this term definition.
+    </p>
+
+
+  <aside class="example ds-selector-tabs changed"
+    title="A sealed term definition can not be overridden">
+    <div class="selectors">
+        <button class="selected" data-selects="original">Original</button>
+        <button data-selects="expanded">Expanded</button>
+        <button data-selects="statements">Statements</button>
+        <button data-selects="turtle">Turtle</button>
+        <a class="playground" target="_blank"></a>
+    </div>
+    <pre class="original selected nohighlight" data-transform="updateExample">
+      <!--
+      {
+        "@context": [
+          {
+            ****"@version": 1.1****,
+            "Person": "http://schema.org/Person",
+            "knows": "http://schema.org/knows",
+            "name": {
+              "@id": "http://schema.org/name",
+              ****"@sealed": true****
+            }
+          },
+          {
+            ****"name": "this_attempt_to_override_name_will_fail"****
+          }
+        ],
+        "@type": "Person",
+        "name": "Manu Sporny",
+        "knows": {
+          "@context": {
+            ****"name": "this_attempt_to_override_name_will_also_fail"****
+          },
+          "name": "Gregg Kellogg"
+        }
+      }
+      -->
+    </pre>
+    <pre class="expanded nohighlight"
+         data-transform="updateExample"
+         data-result-for="A sealed term definition can not be overridden-original">
+    <!--
+    [{
+      "@type": ["http://schema.org/Person"],
+      "http://schema.org/name": [{"@value": "Manu Sporny"}],
+      "http://schema.org/knows": [{
+        "http://schema.org/name": [{"@value": "Gregg Kellogg"}]
+      }]
+    }]
+    -->
+    </pre>
+    <table class="statements"
+           data-result-for="A sealed term definition can not be overridden-expanded"
+           data-to-rdf>
+      <thead><tr><th>Subject</th><th>Property</th><th>Value</th></tr></thead>
+      <tbody>
+        <tr><td>_:b0</td><td>rdf:type</td><td>schema:Person</td></tr>
+        <tr><td>_:b0</td><td>schema:name</td><td>Manu Sporny</td></tr>
+        <tr><td>_:b0</td><td>schema:knows</td><td>_:b1</td></tr>
+        <tr><td>_:b1</td><td>schema:name</td><td>Gregg Kellogg</td></tr>
+      </tbody>
+    </table>
+    <pre class="turtle"
+         data-content-type="text/turtle"
+         data-result-for="A sealed term definition can not be overridden-expanded"
+         data-transform="updateExample"
+         data-to-rdf>
+      <!--
+      @prefix schema: <http://schema.org/> .
+
+      [
+        a schema:Person;
+        schema:name "Manu Sporny";
+        schema:knows [
+          schema:name "Gregg Kellogg"
+        ]
+      ] .
+      -->
+    </pre>
+  </aside>
+
+  <p>When all or most term definitions of a context need to be sealed,
+    it is possible to add a member <code>@sealed</code> set to <code>true</code>
+    to the context itself.
+    It has the same effect as sealing each of its term definitions individually.
+    Exceptions can be made by adding a member <code>@sealed</code> set to <code>false</code>
+    in some term definitions.
+    </p>
+
+  <aside class="example ds-selector-tabs changed"
+    title="A sealed @context with an exception">
+    <div class="selectors">
+        <button class="selected" data-selects="original">Original</button>
+        <button data-selects="expanded">Expanded</button>
+        <button data-selects="statements">Statements</button>
+        <button data-selects="turtle">Turtle</button>
+        <a class="playground" target="_blank"></a>
+    </div>
+    <pre class="original selected nohighlight" data-transform="updateExample">
+      <!--
+      {
+        "@context": [
+          {
+            ****"@version": 1.1****,
+            ****"@sealed": true****,
+            "name": "http://schema.org/name",
+            "member": "http://schema.org/member",
+            "Person": {
+              "@id": "http://schema.org/Person",
+              ****"@sealed": false****
+            }
+          }
+        ],
+        "name": "Digital Bazaar",
+        "member": {
+          "@context": {
+            "Person": "http://xmlns.com/foaf/0.1/Person",
+            "name": "this_attempt_to_override_name_will_fail"
+          },
+          "@type": "Person",
+          "name": "Manu Sporny"
+        }
+      }
+      -->
+    </pre>
+    <pre class="expanded nohighlight"
+         data-transform="updateExample"
+         data-result-for="A sealed @context with an exception-original">
+    <!--
+    [{
+      "http://schema.org/name": [{"@value": "Digital Bazaar"}],
+      "http://schema.org/member": [
+        {
+          "@type": ["http://xmlns.com/foaf/0.1/Person"],
+          "http://schema.org/name": [{"@value": "Manu Sporny"}]
+        }
+      ]
+    }]
+    -->
+    </pre>
+    <table class="statements"
+           data-result-for="A sealed @context with an exception-expanded"
+           data-to-rdf>
+      <thead><tr><th>Subject</th><th>Property</th><th>Value</th></tr></thead>
+      <tbody>
+        <tr><td>_:b0</td><td>schema:name</td><td>Digital Bazaar</td></tr>
+        <tr><td>_:b0</td><td>schema:member</td><td>_:b1</td></tr>
+        <tr><td>_:b1</td><td>rdf:type</td><td>foaf:Person</td></tr>
+        <tr><td>_:b1</td><td>schema:name</td><td>Manu Sporny</td></tr>
+      </tbody>
+    </table>
+    <pre class="turtle"
+         data-content-type="text/turtle"
+         data-result-for="A sealed @context with an exception-expanded"
+         data-transform="updateExample"
+         data-to-rdf>
+      <!--
+      @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+      @prefix schema: <http://schema.org/> .
+
+      [
+        schema:name "Digital Bazaar";
+        schema:member [
+          a foaf:Person;
+          schema:name "Manu Sporny"
+        ]
+      ] .
+      -->
+    </pre>
+  </aside>
+
+  <p>While sealed term definitions can not be directly overridden,
+      it is worth noting that setting <code>@context</code> to <code>null</code>
+      will erase everything from the active context,
+      <em>including</em> sealed term definitions.
+      </p>
+
+  <aside class="example ds-selector-tabs changed"
+    title="@context null erases sealed term definitions">
+    <div class="selectors">
+        <button class="selected" data-selects="original">Original</button>
+        <button data-selects="expanded">Expanded</button>
+        <button data-selects="statements">Statements</button>
+        <button data-selects="turtle">Turtle</button>
+        <a class="playground" target="_blank"></a>
+    </div>
+    <pre class="original selected nohighlight" data-transform="updateExample">
+      <!--
+      {
+        "@context": [
+          {
+            ****"@version": 1.1****,
+            ****"@sealed": true****,
+            "Organization": "http://schema.org/Organization",
+            "name": "http://schema.org/name",
+            "employee": {
+              "@id": "http://schema.org/employee",
+              ****"@context": null****
+            }
+          }
+        ],
+        "@type": "Organization",
+        "name": "Digital Bazaar",
+        "employee" : {
+          #### — because of "@context": null in the scoped context, ####
+          #### — the active context at this point is empty; ####
+          #### — so we can (and we must) redefine "name" below ####
+          "@context": {
+            ****"name": "http://xmlns.com/foaf/0.1/name"****
+          },
+          "name": "Manu Sporny"
+        }
+      }
+      -->
+    </pre>
+    <pre class="expanded nohighlight"
+         data-transform="updateExample"
+         data-result-for="@context null erases sealed term definitions-original">
+    <!--
+    [{
+      "@type": ["http://schema.org/Organization"],
+      "http://schema.org/name": [{"@value": "Digital Bazaar"}],
+      "http://schema.org/employee": [
+        {
+          "http://xmlns.com/foaf/0.1/name": [{"@value": "Manu Sporny"}]
+        }
+      ]
+    }]
+    -->
+    </pre>
+    <table class="statements"
+           data-result-for="@context null erases sealed term definitions-expanded"
+           data-to-rdf>
+      <thead><tr><th>Subject</th><th>Property</th><th>Value</th></tr></thead>
+      <tbody>
+        <tr><td>_:b0</td><td>rdf:type</td><td>schema:Organization</td></tr>
+        <tr><td>_:b0</td><td>schema:name</td><td>Digital Bazaar</td></tr>
+        <tr><td>_:b0</td><td>schema:employee</td><td>_:b1</td></tr>
+        <tr><td>_:b1</td><td>foaf:name</td><td>Manu Sporny</td></tr>
+      </tbody>
+    </table>
+    <pre class="turtle"
+         data-content-type="text/turtle"
+         data-result-for="@context null erases sealed term definitions-expanded"
+         data-transform="updateExample"
+         data-to-rdf>
+      <!--
+      @prefix foaf: <http://xmlns.com/foaf/0.1/>.
+      @prefix schema: <http://schema.org/>.
+
+      [
+        a schema:Organization;
+        schema:name "Digital Bazaar";
+        schema:employee [
+          foaf:name "Manu Sporny"
+        ];
+      ] .
+      -->
+    </pre>
+  </aside>
+  <p class="note">By preventing terms from being overridden,
+    sealing also prevents any adaptation of a term
+    (e.g., defining a more precise datatype, restricting the term's use to lists, etc.).
+    This kind of adaptation is frequent with some general purpose contexts,
+    for which sealing would therefore hinder their usability.
+    As a consequence, context publishers should use this feature with care.
+    </p>
+
+  <p class="note">Sealed term definitions are a new feature in JSON-LD 1.1, requiring
+    <a>processing mode</a> set to <code>json-ld-1.1</code>.</p>
+</section>
 </section>
 
 <section class="informative"><h2>Describing Values</h2>