Fix typo: requestor -> requester

Author: changeworld

articles/cdn/cdn-overview.md

@@ -39,7 +39,7 @@ For a list of current content delivery network node locations, see [Azure Conten
 
 3. The origin server returns the file to an edge server in the POP.
 
-4. An edge server in the POP caches the file and returns the file to the original requestor (Alice). The file remains cached on the edge server in the POP until the time to live (TTL) specified by its HTTP headers expires. If the origin server didn't specify a TTL, the default TTL is seven days.
+4. An edge server in the POP caches the file and returns the file to the original requester (Alice). The file remains cached on the edge server in the POP until the time to live (TTL) specified by its HTTP headers expires. If the origin server didn't specify a TTL, the default TTL is seven days.
 
 5. More users can then request the same file by using the same URL that Alice used, and gets directed to the same POP.