diff --git a/appendices/glossary.txt b/appendices/glossary.txt
index b6e6a05a..7fad3431 100644
--- a/appendices/glossary.txt
+++ b/appendices/glossary.txt
@@ -1021,7 +1021,7 @@ Render Pass Instance::
     A use of a render pass in a command buffer.
 
 Required Extensions::
-    Extensions which must: be enabled to use a specific enabled extension
+    Extensions that must: be enabled alongside extensions dependent on them
     (see <<extended-functionality-extensions-dependencies, Extension
     Dependencies>>).
 
diff --git a/chapters/extensions.txt b/chapters/extensions.txt
index 1d137122..03782080 100644
--- a/chapters/extensions.txt
+++ b/chapters/extensions.txt
@@ -223,6 +223,15 @@ wrapped by the validation layers.
 See the <<LoaderAndValidationLayers, "`Vulkan Loader Specification and
 Architecture Overview`">> document for additional information.
 
+[NOTE]
+.Note
+====
+Valid Usage sections for individual commands and structures do not currently
+contain which extensions have to be enabled in order to make their use
+valid, although it might do so in the future.
+It is defined only in the <<fundamentals-validusage-extensions>> section.
+====
+
 [open,refpage='vkEnumerateInstanceExtensionProperties',desc='Returns up to requested number of global extension properties',type='protos']
 --
 
@@ -344,21 +353,22 @@ endif::VK_VERSION_1_1,VK_KHR_get_physical_device_properties2[]
 == Extension Dependencies
 
 Some extensions are dependent on other extensions to function.
-To use extensions with dependencies, such _required extensions_ must: also
-be enabled through the same API mechanisms when creating an instance with
-flink:vkCreateInstance or a device with flink:vkCreateDevice.
+To enable extensions with dependencies, such _required extensions_ must:
+also be enabled through the same API mechanisms when creating an instance
+with flink:vkCreateInstance or a device with flink:vkCreateDevice.
 Each extension which has such dependencies documents them in the
 <<extensions, appendix summarizing that extension>>.
 
-[NOTE]
-.Note
-====
-The Specification does not currently include required extensions in Valid
-Usage statements for individual commands and structures, although it might
-do so in the future.
-Nonetheless, applications must: not use any extension functionality if
-dependencies of that extension are not enabled.
-====
+If an extension is supported (as queried by
+flink:vkEnumerateInstanceExtensionProperties or
+flink:vkEnumerateDeviceExtensionProperties), then _required extensions_ of
+that extension must: also be supported for the same instance or
+physical device. 
+
+Any device extension that has an instance extension dependency that is not
+enabled by flink:vkCreateInstance is considered to be unsupported, hence it
+must: not be returned by flink:vkEnumerateDeviceExtensionProperties for any
+slink:VkPhysicalDevice child of the instance.
 
 
 [[extended-functionality-extensions-compatibility]]