diff --git a/mod/glossary/edit_form.php b/mod/glossary/edit_form.php
index f6253b0a78a..e68014df314 100644
--- a/mod/glossary/edit_form.php
+++ b/mod/glossary/edit_form.php
@@ -107,6 +107,13 @@ class mod_glossary_entry_form extends moodleform {
 
         $id = (int)$data['id'];
         $data['concept'] = trim($data['concept']);
+        $aliases = explode("\r\n", trim($data['aliases']));
+        foreach ($aliases as $alias) {
+            // Check if the alias is just a single character and that it doesn't match reserved symbols.
+            if (strlen(trim($alias)) == 1 && preg_match('/[$-\/:-?{-~!"^_`\[\]]/', trim($alias))) {
+                $errors['aliases'] = get_string('errreservedkeywords', 'glossary');
+            }
+        }
 
         if ($id) {
             //We are updating an entry, so we compare current session user with
diff --git a/mod/glossary/lang/en/glossary.php b/mod/glossary/lang/en/glossary.php
index 35500edabfa..21765a3f94d 100644
--- a/mod/glossary/lang/en/glossary.php
+++ b/mod/glossary/lang/en/glossary.php
@@ -166,6 +166,7 @@ $string['errconceptalreadyexists'] = 'This concept already exists. No duplicates
 $string['errdeltimeexpired'] = 'You can\'t delete this. Time expired!';
 $string['erredittimeexpired'] = 'The editing time for this entry has expired.';
 $string['errorparsingxml'] = 'Errors occurred while parsing the file. Make sure it is valid XML syntax.';
+$string['errreservedkeywords'] = 'Some/All of the entered keywords cannot be used as they are reserved.';
 $string['eventcategorycreated'] = 'Category has been created';
 $string['eventcategorydeleted'] = 'Category has been deleted';
 $string['eventcategoryupdated'] = 'Category has been updated';
diff --git a/mod/glossary/tests/behat/create_entry.feature b/mod/glossary/tests/behat/create_entry.feature
new file mode 100644
index 00000000000..09833e0cafb
--- /dev/null
+++ b/mod/glossary/tests/behat/create_entry.feature
@@ -0,0 +1,33 @@
+@mod @mod_glossary @javascript
+Feature: Create a glossary entry. As a user
+  I should be able to enter an entry without
+  using reserved keywords
+
+  Background:
+    Given the following "users" exist:
+      | username | firstname | lastname | email                |
+      | teacher1 | Teacher   | 1        | teacher1@example.com |
+      | student1 | Student   | 1        | student1@example.com |
+    And the following "courses" exist:
+      | fullname | shortname | format |
+      | Course 1 | C1        | topics |
+    And the following "course enrolments" exist:
+      | user     | course | role           |
+      | teacher1 | C1     | editingteacher |
+      | student1 | C1     | student        |
+    And I log in as "teacher1"
+    And I am on "Course 1" course homepage with editing mode on
+    And I add a "Glossary" to section "1" and I fill the form with:
+      | Name | Test glossary |
+      | Description | A glossary about dreams! |
+    And I log out
+
+  Scenario: Glossary entry edition of custom tags works as expected
+    Given I am on the "Test glossary" "glossary activity" page logged in as "teacher1"
+    And I press "Add entry"
+    And I set the following fields to these values:
+      | Concept    | Dummy first entry               |
+      | Definition | Dream is the start of a journey |
+      | Keyword(s) | "                               |
+    And I press "Save changes"
+    Then I should see "Some/All of the entered keywords cannot be used as they are reserved."