Cell collapse/expand is not called "Toggle".

IPython/frontend/html/notebook/static/js/codecell.js

@@ -352,6 +352,14 @@ var IPython = (function (IPython) {
     };
 
 
+    CodeCell.prototype.toggle_output = function () {
+        if (this.collapsed) {
+            this.expand();
+        } else {
+            this.collapse();
+        };
+    };
+
     CodeCell.prototype.set_input_prompt = function (number) {
         var n = number || ' ';
         this.input_prompt_number = n

IPython/frontend/html/notebook/static/js/notebook.js

@@ -480,6 +480,13 @@ var IPython = (function (IPython) {
     };
 
 
+    Notebook.prototype.toggle_output = function (index) {
+        var i = this.index_or_selected(index);
+        this.cells()[i].toggle_output();
+        this.dirty = true;
+    };
+
+
     Notebook.prototype.set_autoindent = function (state) {
         var cells = this.cells();
         len = cells.length;

IPython/frontend/html/notebook/templates/notebook.html

@@ -95,9 +95,8 @@
                      <span class="button_label">Format</span> 
                 </div>
                 <div class="section_row">
-                    <span id="toggle_output" class="section_row_buttons">
-                        <button id="collapse_cell">Collapse</button>
-                        <button id="expand_cell">Expand</button>
+                    <span id="cell_output" class="section_row_buttons">
+                        <button id="toggle_output">Toggle</button>
                         <button id="clear_all_output">ClearAll</button>
                     </span>
                     <span class="button_label">Output</span>