diff --git a/lecture4.html b/lecture4.html
index 9193fab..9140229 100644
--- a/lecture4.html
+++ b/lecture4.html
@@ -563,7 +563,7 @@ <h1>Push promise</h1>
                 <ul class="xx-small">
                     <li><code>PUSH_PROMISE</code> frames</li>
                     <ul>
-                        <li>A singnal that the server intents to push resources to the client</li>
+                        <li>A signal that the server intents to push resources to the client</li>
                         <li>The client needs to know which resources the server intends to push to avoid creating
                             duplicate requests for these resources.</li>
                     </ul>