diff --git a/index.html b/index.html
index e24886f..2096203 100644
--- a/index.html
+++ b/index.html
@@ -267,7 +267,11 @@ <h2>Use Cases and Requirements</h2>
     <section id="out-of-the-box-interoperability">
       <h2>Out-of-the-Box Interoperability</h2>
       <p>
-        The definition of out-of-the-box interoperability used in this
+        At a high level, out-of-the-box interoperability means that a <a href="#dfn-consumer">Consumer</a> is guaranteed to be able to
+        use every capability of a <a href="#dfn-thing">Thing</a>, without Thing-specific customization.
+      </p>
+      <p>
+        The full definition of out-of-the-box interoperability used in this
         specification includes multiple layers.
         The following classification adopts terminology from the
         "H2020 – CREATE-IoT Project - Recommendations for commonalities and