diff --git a/doc/lispref/files.texi b/doc/lispref/files.texi
index 60834338423..9a1b2cd217f 100644
--- a/doc/lispref/files.texi
+++ b/doc/lispref/files.texi
@@ -3081,12 +3081,12 @@ making connections when they don't exist.
 @end defun
 
 @defun unhandled-file-name-directory filename
-This function returns the name of a directory that is not magic.  It
-turns @var{filename} into a directory name if that is not magic.  For a
-magic file name, it invokes the file name handler, which therefore
-decides what value to return.  If @var{filename} is not accessible
-from a local process, then the file name handler should indicate it by
-returning @code{nil}.
+This function returns the name of a directory that is not magic.  For
+a non-magic @var{filename} it returns the corresponding directory name
+(@pxref{Directory Names}).  For a magic @var{filename}, it invokes the
+file name handler, which therefore decides what value to return.  If
+@var{filename} is not accessible from a local process, then the file
+name handler should indicate that by returning @code{nil}.
 
 This is useful for running a subprocess; every subprocess must have a
 non-magic directory to serve as its current directory, and this function