diff --git a/docs/guides/index.md b/docs/guides/index.md
index c8c83d18..32373c27 100644
--- a/docs/guides/index.md
+++ b/docs/guides/index.md
@@ -9,7 +9,7 @@ customjs: //survey.g.doubleclick.net/async_survey?site=dgxvheagfp4ai24o6y2ammm5f
 ---
 
 This document introduces you to gRPC and protocol buffers. gRPC can use
-protocol buffers as both its IDL and as its underlying message
+protocol buffers as both its Interface Definition Language (IDL) and as its underlying message
 interchange format. If you’re new to gRPC and/or protocol buffers, read this!
 If you just want to dive in and see gRPC in action first,
 see our [Quick Starts](../quickstart).