diff --git a/functions/zlib.xml b/functions/zlib.xml
index a264b1447b..6762de2d6c 100644
--- a/functions/zlib.xml
+++ b/functions/zlib.xml
@@ -609,7 +609,7 @@ gzclose ($zd);
   <refentry id="function.gzcompress">
    <refnamediv>
     <refname>gzcompress</refname>
-    <refpurpose>Gz-compress a string</refpurpose>
+    <refpurpose>Deflate a string</refpurpose>
    </refnamediv>
    <refsect1>
     <title>Description</title>
@@ -623,11 +623,19 @@ gzclose ($zd);
      </funcprototype>
     </funcsynopsis>
     <para>
-     This function returns a gzip-compressed version of the input
-     <parameter>data</parameter> or false on errors. The optional
-     parameter <parameter>level</parameter> can be given as 0 for no
+     This function returns a compressed version of the input
+     <parameter>data</parameter> using the deflate algorithm,
+     or false if an error is encountered. The optional parameter
+     <parameter>level</parameter> can be given as 0 for no
      compression up to 9 for maximum compression.
     </para>
+    <note>
+     <para>
+      This is <emphasis>not</emphasis> the same as gzip compression,
+      which includes some header data. See <function>gzencode</function>
+      for gzip compression.
+     </para>
+    </note>
     <para>
      See also <function>gzuncompress</function>.
     </para>
@@ -637,7 +645,7 @@ gzclose ($zd);
   <refentry id="function.gzuncompress">
    <refnamediv>
     <refname>gzuncompress</refname>
-    <refpurpose>Uncompress a gz-compressed string</refpurpose>
+    <refpurpose>Uncompress a deflated string</refpurpose>
    </refnamediv>
    <refsect1>
     <title>Description</title>
@@ -652,9 +660,9 @@ gzclose ($zd);
     </funcsynopsis>
     <para>			
      This function takes <parameter>data</parameter> compressed by
-     <function>gzcompress</function> and returns the orignial
+     <function>gzcompress</function> and returns the original
      uncompressed data or false on error.  The function will return an
-     error if the uncompressed data is more than 256 times the lenght
+     error if the uncompressed data is more than 256 times the length
      of the compressed input <parameter>data</parameter> or more than
      the optional parameter <parameter>length</parameter>.
     </para>