diff --git a/collects/scribblings/reference/parameters.scrbl b/collects/scribblings/reference/parameters.scrbl
index 0c99b660d7..45babe982f 100644
--- a/collects/scribblings/reference/parameters.scrbl
+++ b/collects/scribblings/reference/parameters.scrbl
@@ -126,7 +126,7 @@ is the same as a nested series of single-parameter @scheme[parameterize]
 forms.}
 
 
-@defproc[(make-derived-parameter [v any/c]
+@defproc[(make-derived-parameter [parameter parameter?]
                                  [guard (any/c . -> . any)]
                                  [wrap (any/c . -> . any)])
          parameter?]{