diff --git a/doc/rules.txt b/doc/rules.txt
index d5e2c417..bfea1eae 100644
--- a/doc/rules.txt
+++ b/doc/rules.txt
@@ -158,3 +158,10 @@ There are several built-in functions, which may be used by rules:
 - Need to distinguish between regular time and over time, with different rates
   and limits.
 
+- The general form is:
+
+    $ timew define A B C
+
+    define A
+      B C
+