diff --git a/topics/reference_guide/custom_language_support/implementing_lexer.md b/topics/reference_guide/custom_language_support/implementing_lexer.md
index a6d377ba6..9b41e7054 100644
--- a/topics/reference_guide/custom_language_support/implementing_lexer.md
+++ b/topics/reference_guide/custom_language_support/implementing_lexer.md
@@ -67,6 +67,8 @@ Custom language plugins should reuse these token types wherever applicable.
 For all other token types, the plugin needs to create new [`IElementType`](%gh-ic%/platform/core-api/src/com/intellij/psi/tree/IElementType.java) instances and associate with the language in which the token type is used.
 The same [`IElementType`](%gh-ic%/platform/core-api/src/com/intellij/psi/tree/IElementType.java) instance should be returned every time a particular token type is encountered by the lexer.
 
+Groups of related types (e.g., keywords) can be defined using [`TokenSet`](%gh-ic%/platform/core-api/src/com/intellij/psi/tree/TokenSet.java).
+
 **Example:**
 [Token types](%gh-ic%/plugins/properties/properties-psi-api/src/com/intellij/lang/properties/parsing/PropertiesTokenTypes.java) for [Properties language plugin](%gh-ic%/plugins/properties)