diff --git a/core/modules/filters/unknown.js b/core/modules/filters/unknown.js
index 21856766b..1cc5d16e2 100644
--- a/core/modules/filters/unknown.js
+++ b/core/modules/filters/unknown.js
@@ -21,7 +21,7 @@ Export our filter function
 */
 exports["[unknown]"] = function(source,operator,options) {
 	// Check for a user defined filter operator
-	if(operator.operator.charAt(0) === ".") {
+	if(operator.operator.indexOf(".") !== -1) {
 		var variableInfo = options.widget && options.widget.getVariableInfo && options.widget.getVariableInfo(operator.operator);
 		if(variableInfo && variableInfo.srcVariable && variableInfo.srcVariable.isFunctionDefinition) {
 			var list = options.widget.evaluateVariable(operator.operator,{params: operator.operands, source: source});
diff --git a/core/modules/parsers/wikiparser/rules/html.js b/core/modules/parsers/wikiparser/rules/html.js
index 64469e3b2..4dbd6a07c 100644
--- a/core/modules/parsers/wikiparser/rules/html.js
+++ b/core/modules/parsers/wikiparser/rules/html.js
@@ -78,7 +78,7 @@ exports.parseTag = function(source,pos,options) {
 			orderedAttributes: []
 		};
 	// Define our regexps
-	var reTagName = /([a-zA-Z0-9\-\$]+)/g;
+	var reTagName = /([a-zA-Z0-9\-\$\.]+)/g;
 	// Skip whitespace
 	pos = $tw.utils.skipWhiteSpace(source,pos);
 	// Look for a less than sign
@@ -138,7 +138,7 @@ exports.parseTag = function(source,pos,options) {
 
 exports.findNextTag = function(source,pos,options) {
 	// A regexp for finding candidate HTML tags
-	var reLookahead = /<([a-zA-Z\-\$]+)/g;
+	var reLookahead = /<([a-zA-Z\-\$\.]+)/g;
 	// Find the next candidate
 	reLookahead.lastIndex = pos;
 	var match = reLookahead.exec(source);
diff --git a/core/modules/widgets/widget.js b/core/modules/widgets/widget.js
index ecb8a430b..6f9a8e4e1 100755
--- a/core/modules/widgets/widget.js
+++ b/core/modules/widgets/widget.js
@@ -546,8 +546,8 @@ Widget.prototype.makeChildWidget = function(parseTreeNode,options) {
 	var variableDefinitionName = "$" + parseTreeNode.type;
 	if(this.variables[variableDefinitionName]) {
 		var isOverrideable = function() {
-				// Widget is overrideable if it has a double dollar user defined name, or if it is an existing JS widget and we're not in safe mode
-				return parseTreeNode.type.charAt(0) === "$" || (!!self.widgetClasses[parseTreeNode.type] && !$tw.safeMode);
+				// Widget is overrideable if its name contains a period, or if it is an existing JS widget and we're not in safe mode
+				return parseTreeNode.type.indexOf(".") !== -1 || (!!self.widgetClasses[parseTreeNode.type] && !$tw.safeMode);
 			};
 		if(!parseTreeNode.isNotRemappable && isOverrideable()) { 
 			var variableInfo = this.getVariableInfo(variableDefinitionName,{allowSelfAssigned: true});
diff --git a/editions/test/tiddlers/tests/data/transclude/CustomWidget-ActionWidget.tid b/editions/test/tiddlers/tests/data/transclude/CustomWidget-ActionWidget.tid
index 0be77a9a3..296aa6931 100644
--- a/editions/test/tiddlers/tests/data/transclude/CustomWidget-ActionWidget.tid
+++ b/editions/test/tiddlers/tests/data/transclude/CustomWidget-ActionWidget.tid
@@ -12,15 +12,15 @@ title: Output
 title: Actions
 
 \whitespace trim
-<!-- Define the <$$action-mywidget> widget by defining a transcludable variable with that name -->
-\widget $$action-mywidget(one:'Jaguar')
+<!-- Define the <$action.mywidget> widget by defining a transcludable variable with that name -->
+\widget $action.mywidget(one:'Jaguar')
 \whitespace trim
 <$action-setfield $tiddler="Result" $field="text" $value=<<one>>/>
 \end
 
-<$$action-mywidget one="Dingo">
+<$action.mywidget one="Dingo">
 	Crocodile
-</$$action-mywidget>
+</$action.mywidget>
 +
 title: ExpectedResult
 
diff --git a/editions/test/tiddlers/tests/data/transclude/CustomWidget-Simple.tid b/editions/test/tiddlers/tests/data/transclude/CustomWidget-Simple.tid
index 15d0c8d9e..ccb590d4f 100644
--- a/editions/test/tiddlers/tests/data/transclude/CustomWidget-Simple.tid
+++ b/editions/test/tiddlers/tests/data/transclude/CustomWidget-Simple.tid
@@ -12,21 +12,21 @@ title: Output
 title: TiddlerOne
 
 \whitespace trim
-<!-- Define the <$$mywidget> widget by defining a transcludable variable with that name -->
-\widget $$mywidget(one:'Jaguar')
+<!-- Define the <$my.widget> widget by defining a transcludable variable with that name -->
+\widget $my.widget(one:'Jaguar')
 \whitespace trim
 <$text text=<<one>>/>
 <$slot $name="ts-raw">
 	Whale
 </$slot>
 \end
-<$$mywidget one="Dingo">
+<$my.widget one="Dingo">
 	Crocodile
-</$$mywidget>
-<$$mywidget one="BumbleBee">
+</$my.widget>
+<$my.widget one="BumbleBee">
 	Squirrel
-</$$mywidget>
-<$$mywidget/>
+</$my.widget>
+<$my.widget/>
 +
 title: ExpectedResult
 
diff --git a/editions/test/tiddlers/tests/data/transclude/CustomWidget-Slotted-Empty.tid b/editions/test/tiddlers/tests/data/transclude/CustomWidget-Slotted-Empty.tid
index efd1e7041..0ada5100b 100644
--- a/editions/test/tiddlers/tests/data/transclude/CustomWidget-Slotted-Empty.tid
+++ b/editions/test/tiddlers/tests/data/transclude/CustomWidget-Slotted-Empty.tid
@@ -6,13 +6,13 @@ tags: [[$:/tags/wiki-test-spec]]
 title: Output
 
 \whitespace trim
-\widget $$mywidget()
+\widget $my.widget()
 <$slot $name=ts-raw>the body is empty</$slot>
 \end
 
-#<$$mywidget/>
-#<$$mywidget></$$mywidget>
-#<$$mywidget>the body is not empty</$$mywidget>
+#<$my.widget/>
+#<$my.widget></$my.widget>
+#<$my.widget>the body is not empty</$my.widget>
 
 +
 title: ExpectedResult
diff --git a/editions/test/tiddlers/tests/data/transclude/CustomWidget-Slotted.tid b/editions/test/tiddlers/tests/data/transclude/CustomWidget-Slotted.tid
index c10e84127..eb7d61756 100644
--- a/editions/test/tiddlers/tests/data/transclude/CustomWidget-Slotted.tid
+++ b/editions/test/tiddlers/tests/data/transclude/CustomWidget-Slotted.tid
@@ -6,21 +6,21 @@ tags: [[$:/tags/wiki-test-spec]]
 title: Output
 
 \whitespace trim
-\widget $$mywidget(one:'Jaguar')
+\widget $my.widget(one:'Jaguar')
 \whitespace trim
 <$text text=<<one>>/>
 <$slot $name="ts-stuff">
 	Whale
 </$slot>
 \end
-<$$mywidget one="Dingo">
+<$my.widget one="Dingo">
 	<$fill $name="ts-stuff">
 		Crocodile
 	</$fill>
-</$$mywidget>
-<$$mywidget one="BumbleBee">
+</$my.widget>
+<$my.widget one="BumbleBee">
 	Squirrel
-</$$mywidget>
+</$my.widget>
 +
 title: ExpectedResult
 
diff --git a/editions/test/tiddlers/tests/data/transclude/CustomWidget-VariableAttribute.tid b/editions/test/tiddlers/tests/data/transclude/CustomWidget-VariableAttribute.tid
index 8ef700b41..e4e7dbaaf 100644
--- a/editions/test/tiddlers/tests/data/transclude/CustomWidget-VariableAttribute.tid
+++ b/editions/test/tiddlers/tests/data/transclude/CustomWidget-VariableAttribute.tid
@@ -12,17 +12,17 @@ title: Output
 title: TiddlerOne
 
 \whitespace trim
-<!-- Redefine the <$$mywidget> widget by defining a transcludable variable with that name -->
-\widget $$mywidget($variable:'Jaguar')
+<!-- Redefine the <$my.widget> widget by defining a transcludable variable with that name -->
+\widget $my.widget($variable:'Jaguar')
 \whitespace trim
 <$text text=<<$variable>>/>
 <$slot $name="ts-raw">
 	Whale
 </$slot>
 \end
-<$$mywidget $variable="Dingo">
+<$my.widget $variable="Dingo">
 	Crocodile
-</$$mywidget>
+</$my.widget>
 +
 title: ExpectedResult
 
diff --git a/editions/tw5.com/tiddlers/functions/Functions.tid b/editions/tw5.com/tiddlers/functions/Functions.tid
index 3b06dddc7..dadce73a1 100644
--- a/editions/tw5.com/tiddlers/functions/Functions.tid
+++ b/editions/tw5.com/tiddlers/functions/Functions.tid
@@ -21,7 +21,7 @@ Functions can be invoked in several ways:
 * Directly transclude functions with the syntax `<<myfn param:"value">>`
 * Assign functions to widget attributes with the syntax `<div class=<<myfn param:"value">>>`
 * Invoke functions via the [[function Operator]] with the syntax `[function[myfn],[value],...]`
-* Directly invoke functions whose names start with a period as custom filter operators with the syntax `[.myfn[value]]`
+* Directly invoke functions whose names contain a period as custom filter operators with the syntax `[my.fn[value]]` or `[.myfn[value]]`
 
 !! How Functions Work
 
diff --git a/editions/tw5.com/tiddlers/variables/Variable Usage.tid b/editions/tw5.com/tiddlers/variables/Variable Usage.tid
index 2166f206a..bc5f36443 100644
--- a/editions/tw5.com/tiddlers/variables/Variable Usage.tid	
+++ b/editions/tw5.com/tiddlers/variables/Variable Usage.tid	
@@ -150,5 +150,5 @@ Below is an example macro, procedure and function definition.  All three forms o
 *''tiddler titles'' - tiddlers are uniquely identified by their title. The namespace for tiddler titles and variable names are completely separate.
 *''variables'' - \define, <<.wlink SetWidget>>, <<.wlink LetWidget>>, <<.wlink VarsWidget>>, \procedure, \widget, \function all create variables. If the same name is used, then later define will overwrite earlier defined
  *''<<.op function>> filter operator parameter'' - only variables defined using \function can be called using the <<.olink function>> operator
- *''filter operators'' - only the [[javascript defined filter operators|Filter Operators]] and variables defined using \function with name starting with a dot can be called
+ *''filter operators'' - only the [[javascript defined filter operators|Filter Operators]] and variables defined using \function with name containing a dot can be called
  *''widgets'' - variables defined using \widget can be invoked using `<$widget/>` syntax ONLY if the name starts a dollar sign (to override existing javascript defined widgets) or double dollar sign (to define [[custom widgets|Custom Widgets]]). Without the dollar sign prefix, defining variables using \widget is no different than using \procedure.
diff --git a/editions/tw5.com/tiddlers/widgets/Custom Widgets.tid b/editions/tw5.com/tiddlers/widgets/Custom Widgets.tid
index c220302cf..3d762bed2 100644
--- a/editions/tw5.com/tiddlers/widgets/Custom Widgets.tid	
+++ b/editions/tw5.com/tiddlers/widgets/Custom Widgets.tid	
@@ -15,26 +15,21 @@ Custom widgets can also be used to override built-in JavaScript widgets to custo
 Custom widgets are usually defined with the [[Pragma: \widget]]:
 
 ```
-\widget $$my-widget(attribute:"Default value")
+\widget $my.widget(attribute:"Default value")
 This is the widget, and the attribute is <<attribute>>.
 \end
 ```
 
-The name of the widget must start with one or two dollar signs:
-
-* A ''single dollar sign'' is used to override existing core widgets
-** for example, `$text` or `$codeblock`
-* ''Double dollar signs'' are used to define a custom widget
-** for example, `$$mywidget` or `$$acme-logger`
+The name of the widget must start with a dollar sign. If it is a user defined widget that does not override an existing widget then it must include at least one period (dot) within the name (for example `$my.widget` or `$acme.logger`).
 
 !! Using Custom Widgets
 
 Custom widgets are called in the same way as ordinary built-in widgets:
 
 ```
-<$my-widget/>
+<$my.widget/>
 
-<$my-widget attribute="The parameter"/>
+<$my.widget attribute="The parameter"/>
 ```
 
 The attributes that are specified in the widget call are made available as parameter variables.
@@ -45,18 +40,18 @@ Within the definition of a custom widget the content of the calling widget is av
 
 For example:
 
-<<wikitext-example-without-html """\widget $$mywidget(one:'Jaguar')
+<<wikitext-example-without-html """\widget $my.widget(one:'Jaguar')
 <$text text=<<one>>/>
 <$slot $name="ts-raw">
 	Whale
 </$slot>
 \end
 
-<$$mywidget one="Dingo">
+<$my.widget one="Dingo">
 	Crocodile
-</$$mywidget>
+</$my.widget>
 
-<$$mywidget/>""">>
+<$my.widget/>""">>
 
 !! How Custom Widgets Work