diff --git a/xsd/eml-attribute.xsd b/xsd/eml-attribute.xsd
index ebe1fdbc..bcec2900 100644
--- a/xsd/eml-attribute.xsd
+++ b/xsd/eml-attribute.xsd
@@ -1,11 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<xs:schema xmlns:res="eml://ecoinformatics.org/resource-2.2.0" xmlns:doc="eml://ecoinformatics.org/documentation-2.2.0" xmlns:cit="eml://ecoinformatics.org/literature-2.2.0" xmlns:cov="eml://ecoinformatics.org/coverage-2.2.0" xmlns:md="eml://ecoinformatics.org/methods-2.2.0" xmlns="eml://ecoinformatics.org/attribute-2.2.0" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:unit="eml://ecoinformatics.org/units-2.2.0" targetNamespace="eml://ecoinformatics.org/attribute-2.2.0">
+<xs:schema xmlns:res="eml://ecoinformatics.org/resource-2.2.0" xmlns:doc="eml://ecoinformatics.org/documentation-2.2.0" xmlns:cit="eml://ecoinformatics.org/literature-2.2.0" xmlns:cov="eml://ecoinformatics.org/coverage-2.2.0" xmlns:md="eml://ecoinformatics.org/methods-2.2.0" xmlns="eml://ecoinformatics.org/attribute-2.2.0" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:unit="eml://ecoinformatics.org/units-2.2.0" xmlns:sem="eml://ecoinformatics.org/semantics-2.2.0" targetNamespace="eml://ecoinformatics.org/attribute-2.2.0">
   <xs:import namespace="eml://ecoinformatics.org/documentation-2.2.0" schemaLocation="eml-documentation.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/methods-2.2.0" schemaLocation="eml-methods.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/coverage-2.2.0" schemaLocation="eml-coverage.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/literature-2.2.0" schemaLocation="eml-literature.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/resource-2.2.0" schemaLocation="eml-resource.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/units-2.2.0" schemaLocation="eml-unitTypeDefinitions.xsd"/>
+  <xs:import namespace="eml://ecoinformatics.org/semantics-2.2.0" schemaLocation="eml-semantics.xsd"/>
   <xs:annotation>
     <xs:documentation>
     '$RCSfile: eml-attribute.xsd,v $'
@@ -755,6 +756,27 @@
             </xs:appinfo>
           </xs:annotation>
         </xs:element>
+        <xs:element name="annotation" type="sem:SemanticAnnotation"
+                    minOccurs="0" maxOccurs="unbounded">
+          <xs:annotation>
+            <xs:appinfo>
+              <doc:tooltip>Semantic Annotation</doc:tooltip>
+              <doc:summary>A precisely-defined semantic type for this attribute.
+              </doc:summary>
+              <doc:description>An annotation represents a precisely-defined semantic
+                  type that applies to this attribute.  This semantic type is used to
+                  associate precise measurement semantics with the attribute, including 
+                  the property that is being measured (oboe:Characteristic), the entity
+                  that is being measured (oboe:Entity), and the measurement standard for
+                  interpreting values for this attribute (oboe:Standard). Each annotation
+                  consists of a termURI which is the canonical reference fo the term, and
+                  a termLabel that can be used to display the term to users.  The termURI is
+                  typically resolvable to a controlled vocabulary that provides a definition,
+                  relationships to other terms, and multiple labels for displaying the term.
+              </doc:description>
+            </xs:appinfo>
+          </xs:annotation>
+        </xs:element>
       </xs:sequence>
       <xs:group ref="res:ReferencesGroup"/>
     </xs:choice>
diff --git a/xsd/eml-entity.xsd b/xsd/eml-entity.xsd
index 88a6b1b6..564c93e3 100644
--- a/xsd/eml-entity.xsd
+++ b/xsd/eml-entity.xsd
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:con="eml://ecoinformatics.org/constraint-2.2.0" xmlns:res="eml://ecoinformatics.org/resource-2.2.0" xmlns:doc="eml://ecoinformatics.org/documentation-2.2.0" xmlns:cov="eml://ecoinformatics.org/coverage-2.2.0" xmlns:phys="eml://ecoinformatics.org/physical-2.2.0" xmlns:md="eml://ecoinformatics.org/methods-2.2.0" xmlns:att="eml://ecoinformatics.org/attribute-2.2.0" xmlns:txt="eml://ecoinformatics.org/text-2.2.0" xmlns="eml://ecoinformatics.org/entity-2.2.0" targetNamespace="eml://ecoinformatics.org/entity-2.2.0">
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:con="eml://ecoinformatics.org/constraint-2.2.0" xmlns:res="eml://ecoinformatics.org/resource-2.2.0" xmlns:doc="eml://ecoinformatics.org/documentation-2.2.0" xmlns:cov="eml://ecoinformatics.org/coverage-2.2.0" xmlns:phys="eml://ecoinformatics.org/physical-2.2.0" xmlns:md="eml://ecoinformatics.org/methods-2.2.0" xmlns:att="eml://ecoinformatics.org/attribute-2.2.0" xmlns:txt="eml://ecoinformatics.org/text-2.2.0" xmlns:sem="eml://ecoinformatics.org/semantics-2.2.0" xmlns="eml://ecoinformatics.org/entity-2.2.0" targetNamespace="eml://ecoinformatics.org/entity-2.2.0">
   <xs:import namespace="eml://ecoinformatics.org/documentation-2.2.0" schemaLocation="eml-documentation.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/coverage-2.2.0" schemaLocation="eml-coverage.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/physical-2.2.0" schemaLocation="eml-physical.xsd"/>
@@ -8,6 +8,7 @@
   <xs:import namespace="eml://ecoinformatics.org/resource-2.2.0" schemaLocation="eml-resource.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/constraint-2.2.0" schemaLocation="eml-constraint.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/text-2.2.0" schemaLocation="eml-text.xsd"/>
+  <xs:import namespace="eml://ecoinformatics.org/semantics-2.2.0" schemaLocation="eml-semantics.xsd"/>
   <xs:annotation>
     <xs:documentation>
        '$RCSfile: eml-entity.xsd,v $'
@@ -281,6 +282,24 @@
           </xs:appinfo>
         </xs:annotation>
       </xs:element>
+      <xs:element name="annotation" type="sem:SemanticAnnotation"
+                  minOccurs="0" maxOccurs="unbounded">
+        <xs:annotation>
+          <xs:appinfo>
+            <doc:tooltip>Semantic Annotation</doc:tooltip>
+            <doc:summary>A precisely-defined semantic type for this entity.
+            </doc:summary>
+            <doc:description>An annotation represents a precisely-defined semantic
+                 type that applies to this entity.  This semantic type is used to
+                  associate precise measurement semantics with the entity.  Each annotation
+                  consists of a termURI which is the canonical reference fo the term, and 
+                  a termLabel that can be used to display the term to users.  The termURI is
+                  typically resolvable to a controlled vocabulary that provides a definition,
+                  relationships to other terms, and multiple labels for displaying the term.
+            </doc:description>
+          </xs:appinfo>
+        </xs:annotation>
+      </xs:element>
     </xs:sequence>
   </xs:group>
 </xs:schema>
diff --git a/xsd/eml-resource.xsd b/xsd/eml-resource.xsd
index 05393e39..b0a9e8c0 100644
--- a/xsd/eml-resource.xsd
+++ b/xsd/eml-resource.xsd
@@ -1,9 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xml="http://www.w3.org/XML/1998/namespace" xmlns:doc="eml://ecoinformatics.org/documentation-2.2.0" xmlns:txt="eml://ecoinformatics.org/text-2.2.0" xmlns:rp="eml://ecoinformatics.org/party-2.2.0" xmlns:cov="eml://ecoinformatics.org/coverage-2.2.0" xmlns="eml://ecoinformatics.org/resource-2.2.0" targetNamespace="eml://ecoinformatics.org/resource-2.2.0">
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xml="http://www.w3.org/XML/1998/namespace" xmlns:doc="eml://ecoinformatics.org/documentation-2.2.0" xmlns:txt="eml://ecoinformatics.org/text-2.2.0" xmlns:rp="eml://ecoinformatics.org/party-2.2.0" xmlns:cov="eml://ecoinformatics.org/coverage-2.2.0" xmlns:sem="eml://ecoinformatics.org/semantics-2.2.0" xmlns="eml://ecoinformatics.org/resource-2.2.0" targetNamespace="eml://ecoinformatics.org/resource-2.2.0">
   <xs:import namespace="eml://ecoinformatics.org/documentation-2.2.0" schemaLocation="eml-documentation.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/party-2.2.0" schemaLocation="eml-party.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/coverage-2.2.0" schemaLocation="eml-coverage.xsd"/>
   <xs:import namespace="eml://ecoinformatics.org/text-2.2.0" schemaLocation="eml-text.xsd"/>
+  <xs:import namespace="eml://ecoinformatics.org/semantics-2.2.0" schemaLocation="eml-semantics.xsd"/>
   <xs:import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/2009/01/xml.xsd"/>
   
   <xs:annotation>
@@ -390,6 +391,24 @@
           </xs:appinfo>
         </xs:annotation>
       </xs:element>
+      <xs:element name="annotation" type="sem:SemanticAnnotation"
+                  minOccurs="0" maxOccurs="unbounded">
+        <xs:annotation>
+          <xs:appinfo>
+            <doc:tooltip>Semantic Annotation</doc:tooltip>
+            <doc:summary>A precisely-defined semantic type for this resource.
+            </doc:summary>
+            <doc:description>An annotation represents a precisely-defined semantic
+                  type that applies to this resource.  This semantic type is used to
+                  associate precise semantics with the resource.  Each annotation
+                  consists of a termURI which is the canonical reference fo the term, and 
+                  a termLabel that can be used to display the term to users.  The termURI is
+                  typically resolvable to a controlled vocabulary that provides a definition,
+                  relationships to other terms, and multiple labels for displaying the term.
+            </doc:description>
+          </xs:appinfo>
+        </xs:annotation>
+      </xs:element>
     </xs:sequence>
   </xs:group>
   <xs:group name="ReferencesGroup">
diff --git a/xsd/eml-semantics.xsd b/xsd/eml-semantics.xsd
index 701a7669..7e30a9d9 100644
--- a/xsd/eml-semantics.xsd
+++ b/xsd/eml-semantics.xsd
@@ -83,9 +83,12 @@
                   an additional abstraction layer via link resolvers, rather than directly
                   resolving to the term definition itself.  Thus, when resolving the termURI, 
                   software user agents should be prepared to follow multiple redirects before
-                  finally resolving the current location of the term definition.
+                  finally resolving the current location of the term definition. However, there
+                  is no requirement that termURIs need to be resolvable, and metadata parsers should
+                  expect to find termURIs that do not resolve and are only used as unique URIs for the term.
               </doc:description>
-              <doc:example>http://</doc:example>
+              <doc:example>http://ecoinformatics.org/oboe/oboe.1.2/oboe-characteristics.owl#Mass</doc:example>
+              <doc:example>http://ecoinformatics.org/oboe/oboe.1.2/oboe-standards.owl#Kilogram</doc:example>
             </xs:appinfo>
           </xs:annotation>
         </xs:element>
@@ -110,6 +113,8 @@
                   the definition of the term and retrieve additional labels and other metadata
                   about the term for presentation to users.
               </doc:description>
+              <doc:example>Mass</doc:example>
+              <doc:example>Kilogram</doc:example>
               <doc:example>Net Primary Production</doc:example>
               <doc:example>Carbon</doc:example>
               <doc:example>Density</doc:example>