diff --git a/doc/arch.md b/doc/arch.md
index 2788927d6..ac18b1d92 100644
--- a/doc/arch.md
+++ b/doc/arch.md
@@ -1,6 +1,6 @@
 # Architecture
 
-First, read [the terminology](terms).  Given that, this picture better explains
+First, read [the terminology](terms.md).  Given that, this picture better explains
 the overall picture:
 
 <img src="https://docs.google.com/drawings/pub?id=1-0QYgyOnjL7hvdEbq77BzkewPJ6BY-bLYCtYFFii77A&amp;w=768&amp;h=576" width='768' height='576' />