diff --git a/source/preprocessor.tex b/source/preprocessor.tex
index 38c595333c..06aacad72c 100644
--- a/source/preprocessor.tex
+++ b/source/preprocessor.tex
@@ -173,6 +173,17 @@
     \descr{the new-line character}
 \end{bnf}
 
+\pnum
+The implementation can
+process and skip sections of source files conditionally,
+include other source files,
+import macros from header units,
+and replace macros.
+These capabilities are called
+\defn{preprocessing},
+because conceptually they occur
+before translation of the resulting translation unit.
+
 \pnum
 A \defn{preprocessing directive} consists of a sequence of preprocessing tokens
 that satisfies the following constraints:
@@ -304,17 +315,6 @@
 or possibly other whitespace characters
 in translation phase 3).
 
-\pnum
-The implementation can
-process and skip sections of source files conditionally,
-include other source files,
-import macros from header units,
-and replace macros.
-These capabilities are called
-\defn{preprocessing},
-because conceptually they occur
-before translation of the resulting translation unit.
-
 \pnum
 The preprocessing tokens within a preprocessing directive
 are not subject to macro expansion unless otherwise stated.