diff --git a/src/Calculator/Resources/en-US/Resources.resw b/src/Calculator/Resources/en-US/Resources.resw
index d8ec8d5..c4c9967 100644
--- a/src/Calculator/Resources/en-US/Resources.resw
+++ b/src/Calculator/Resources/en-US/Resources.resw
@@ -4045,7 +4045,7 @@
   </data>
   <data name="Periodicity" xml:space="preserve">
     <value>Period</value>
-    <comment>Title for KeyGraphFeatures Periodicity Property</comment>
+    <comment>Title for KeyGraphFeatures Periodicity Property. The period of a mathematical function is the smallest interval in its input values such that its output values repeat every such interval.</comment>
   </data>
   <data name="Range" xml:space="preserve">
     <value>Range</value>