diff --git a/core/generator.js b/core/generator.js
index e9eb663ff..3c6a5c7e1 100644
--- a/core/generator.js
+++ b/core/generator.js
@@ -326,8 +326,8 @@ Blockly.Generator.prototype.FUNCTION_NAME_PLACEHOLDER_ = '{leCUI8hutHZI4480Dc}';
  */
 Blockly.Generator.prototype.provideFunction_ = function(desiredName, code) {
   if (!this.definitions_[desiredName]) {
-    var functionName =
-        this.variableDB_.getDistinctName(desiredName, this.NAME_TYPE);
+    var functionName = this.variableDB_.getDistinctName(desiredName,
+        Blockly.Procedures.NAME_TYPE);
     this.functionNames_[desiredName] = functionName;
     var codeText = code.join('\n').replace(
         this.FUNCTION_NAME_PLACEHOLDER_REGEXP_, functionName);
diff --git a/generators/dart/math.js b/generators/dart/math.js
index aae008a2c..2f7c8027a 100644
--- a/generators/dart/math.js
+++ b/generators/dart/math.js
@@ -317,7 +317,7 @@ Blockly.Dart['math_on_list'] = function(block) {
       // This operation exclude null and values that are not int or float:
       //   math_mean([null,null,"aString",1,9]) == 5.0.
       var functionName = Blockly.Dart.provideFunction_(
-          'math_average',
+          'math_mean',
           [ 'num ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
               '(List myList) {',
             '  // First filter list for numbers only.',
diff --git a/generators/dart/procedures.js b/generators/dart/procedures.js
index 4f1b9789e..0085c6bf6 100644
--- a/generators/dart/procedures.js
+++ b/generators/dart/procedures.js
@@ -57,7 +57,8 @@ Blockly.Dart['procedures_defreturn'] = function(block) {
   var code = returnType + ' ' + funcName + '(' + args.join(', ') + ') {\n' +
       branch + returnValue + '}';
   code = Blockly.Dart.scrub_(block, code);
-  Blockly.Dart.definitions_[funcName] = code;
+  // Add % so as not to collide with helper functions in definitions list.
+  Blockly.Dart.definitions_['%' + funcName] = code;
   return null;
 };
 
diff --git a/generators/javascript/math.js b/generators/javascript/math.js
index 17451a5b2..0a7d14621 100644
--- a/generators/javascript/math.js
+++ b/generators/javascript/math.js
@@ -251,7 +251,7 @@ Blockly.JavaScript['math_on_list'] = function(block) {
       code = 'Math.max.apply(null, ' + list + ')';
       break;
     case 'AVERAGE':
-      // math_median([null,null,1,3]) == 2.0.
+      // mathMean([null,null,1,3]) == 2.0.
       var functionName = Blockly.JavaScript.provideFunction_(
           'mathMean',
           [ 'function ' + Blockly.JavaScript.FUNCTION_NAME_PLACEHOLDER_ +
@@ -264,7 +264,7 @@ Blockly.JavaScript['math_on_list'] = function(block) {
       code = functionName + '(' + list + ')';
       break;
     case 'MEDIAN':
-      // math_median([null,null,1,3]) == 2.0.
+      // mathMedian([null,null,1,3]) == 2.0.
       var functionName = Blockly.JavaScript.provideFunction_(
           'mathMedian',
           [ 'function ' + Blockly.JavaScript.FUNCTION_NAME_PLACEHOLDER_ +
diff --git a/generators/javascript/procedures.js b/generators/javascript/procedures.js
index f2ca15ac1..04845f9bd 100644
--- a/generators/javascript/procedures.js
+++ b/generators/javascript/procedures.js
@@ -49,14 +49,15 @@ Blockly.JavaScript['procedures_defreturn'] = function(block) {
     returnValue = '  return ' + returnValue + ';\n';
   }
   var args = [];
-  for (var x = 0; x < block.arguments_.length; x++) {
-    args[x] = Blockly.JavaScript.variableDB_.getName(block.arguments_[x],
+  for (var i = 0; i < block.arguments_.length; i++) {
+    args[i] = Blockly.JavaScript.variableDB_.getName(block.arguments_[i],
         Blockly.Variables.NAME_TYPE);
   }
   var code = 'function ' + funcName + '(' + args.join(', ') + ') {\n' +
       branch + returnValue + '}';
   code = Blockly.JavaScript.scrub_(block, code);
-  Blockly.JavaScript.definitions_[funcName] = code;
+  // Add % so as not to collide with helper functions in definitions list.
+  Blockly.JavaScript.definitions_['%' + funcName] = code;
   return null;
 };
 
@@ -70,8 +71,8 @@ Blockly.JavaScript['procedures_callreturn'] = function(block) {
   var funcName = Blockly.JavaScript.variableDB_.getName(
       block.getFieldValue('NAME'), Blockly.Procedures.NAME_TYPE);
   var args = [];
-  for (var x = 0; x < block.arguments_.length; x++) {
-    args[x] = Blockly.JavaScript.valueToCode(block, 'ARG' + x,
+  for (var i = 0; i < block.arguments_.length; i++) {
+    args[i] = Blockly.JavaScript.valueToCode(block, 'ARG' + i,
         Blockly.JavaScript.ORDER_COMMA) || 'null';
   }
   var code = funcName + '(' + args.join(', ') + ')';
@@ -83,8 +84,8 @@ Blockly.JavaScript['procedures_callnoreturn'] = function(block) {
   var funcName = Blockly.JavaScript.variableDB_.getName(
       block.getFieldValue('NAME'), Blockly.Procedures.NAME_TYPE);
   var args = [];
-  for (var x = 0; x < block.arguments_.length; x++) {
-    args[x] = Blockly.JavaScript.valueToCode(block, 'ARG' + x,
+  for (var i = 0; i < block.arguments_.length; i++) {
+    args[i] = Blockly.JavaScript.valueToCode(block, 'ARG' + i,
         Blockly.JavaScript.ORDER_COMMA) || 'null';
   }
   var code = funcName + '(' + args.join(', ') + ');\n';
diff --git a/generators/lua/procedures.js b/generators/lua/procedures.js
index e8a37c079..9bdcc416b 100644
--- a/generators/lua/procedures.js
+++ b/generators/lua/procedures.js
@@ -58,7 +58,8 @@ Blockly.Lua['procedures_defreturn'] = function(block) {
   var code = 'function ' + funcName + '(' + args.join(', ') + ')\n' +
       branch + returnValue + 'end\n';
   code = Blockly.Lua.scrub_(block, code);
-  Blockly.Lua.definitions_[funcName] = code;
+  // Add % so as not to collide with helper functions in definitions list.
+  Blockly.Lua.definitions_['%' + funcName] = code;
   return null;
 };
 
diff --git a/generators/php/procedures.js b/generators/php/procedures.js
index 75903e31c..1fd4cc872 100644
--- a/generators/php/procedures.js
+++ b/generators/php/procedures.js
@@ -70,7 +70,8 @@ Blockly.PHP['procedures_defreturn'] = function(block) {
   var code = 'function ' + funcName + '(' + args.join(', ') + ') {\n' +
       globals + branch + returnValue + '}';
   code = Blockly.PHP.scrub_(block, code);
-  Blockly.PHP.definitions_[funcName] = code;
+  // Add % so as not to collide with helper functions in definitions list.
+  Blockly.PHP.definitions_['%' + funcName] = code;
   return null;
 };
 
diff --git a/generators/python/procedures.js b/generators/python/procedures.js
index 6d11df8c2..daa7386aa 100644
--- a/generators/python/procedures.js
+++ b/generators/python/procedures.js
@@ -72,7 +72,8 @@ Blockly.Python['procedures_defreturn'] = function(block) {
   var code = 'def ' + funcName + '(' + args.join(', ') + '):\n' +
       globals + branch + returnValue;
   code = Blockly.Python.scrub_(block, code);
-  Blockly.Python.definitions_[funcName] = code;
+  // Add % so as not to collide with helper functions in definitions list.
+  Blockly.Python.definitions_['%' + funcName] = code;
   return null;
 };