diff --git a/ssn/chapters/OMS.html b/ssn/chapters/OMS.html
index f426d67b..a3458d96 100644
--- a/ssn/chapters/OMS.html
+++ b/ssn/chapters/OMS.html
@@ -20,8 +20,8 @@ <h4>OMS Requirement</h4>
     structure model.
     The URI for each formal Requirement relating to a class or property in OMS denotes the UML class or
     property.
-    The predicate `ogc-ms:implements` links a SOSA term to the corresponding OMS class or property,
-    and `ogc-ms:implementedBy` its inverse, defined as follows:
+    The predicate `ogc-ms:implements` and its inverse `ogc-ms:implementedBy` link a SOSA term to
+    the corresponding OMS class or property, defined as follows:
   </p>
 
   <pre class="turtle">
@@ -33,8 +33,8 @@ <h4>OMS Requirement</h4>
 </pre>
 
   <p class="note">
-    The OMS Extension Module provides an implementation of most but not all of the classes and properties defined in [[OMS]]. 
-    Furthermore, the axiomatization here does not capture the details of the ranges of all properties.
+    The OMS Extension Module implements most, but not all, of the classes and properties defined in [[OMS]]. 
+    Furthermore, the axioms in this module do not capture the details of the ranges of all properties.
     Future editions of SSN may provide a more complete implementation.  
   </p>
 
@@ -246,7 +246,7 @@ <h5><dfn>sosa-oms:hasPreparationStep</dfn></h5>
     </p>
     <p>
       <em>has preparation step</em> &mdash;
-      relation from a Sample to a PreparationStep used to prepare it
+      relation from a Sample to a PreparationStep used to prepare the Sample
     </p>
     <dl>
       <dt>Domain Includes</dt>
@@ -365,7 +365,7 @@ <h5><dfn>sosa-oms:makesObservationCollection</dfn></h5>
     </p>
     <p>
       <em>makes observation collection</em> &mdash;
-      relation from a Platform to an ObservationCollection arising from it
+      relation from a Platform to an ObservationCollection arising from a Deployment on the Platform
     </p>
     <p class="note">
       In order to indicate potential Observations at a Platform, an empty ObservationCollection can be provided.
@@ -636,7 +636,7 @@ <h5><dfn>sosa-oms:samplePreparationStep</dfn></h5>
     </p>
     <p>
       <em>sample preparation step</em> &mdash;
-      link from a PreparationProcedure to a PreparationStep used in it
+      link from a PreparationProcedure to a PreparationStep used in the PreparationProcedure
     </p>
     <dl>
       <dt>Domain Includes</dt>
diff --git a/ssn/rdf/ontology/extensions/sosa-oms.ttl b/ssn/rdf/ontology/extensions/sosa-oms.ttl
index d70ebb9e..8cc6a73d 100644
--- a/ssn/rdf/ontology/extensions/sosa-oms.ttl
+++ b/ssn/rdf/ontology/extensions/sosa-oms.ttl
@@ -338,7 +338,7 @@ sosa-oms:madeOnPlatform
 sosa-oms:makesObservationCollection
   a owl:ObjectProperty ;
   rdfs:label "makes observation collection"@en ;
-  skos:definition "relation from a Platform to an ObservationCollection arising from it."@en ;
+  skos:definition "relation from a Platform to an ObservationCollection arising from a Deployment on the Platform"@en ;
   skos:note """
   In order to indicate potential Observations at a Platform, an empty ObservationCollection can be provided. This mimics the semantics of the OMS ObservingCapability class.
   """@en ;
@@ -423,7 +423,7 @@ sosa-oms:samplePreparationStep
   a owl:ObjectProperty ;
   ogc-ms:implements <http://www.opengis.net/spec/om/3.0/req/sam-cpt/PreparationProcedure/samplePreparationStep-sem> ;
   rdfs:label "sample preparation step"@en ;
-  skos:definition "A PreparationStep that uses the PreparationProcedure."@en ;
+  skos:definition "link from a PreparationProcedure to a PreparationStep used in the PreparationProcedure"@en ;
   schema:domainIncludes sosa-oms:PreparationProcedure ;
   schema:rangeIncludes sosa-oms:PreparationStep ;
   owl:inverseOf sosa-oms:processingDetails ;