diff --git a/Home.md b/Home.md
index 48091a2..67eea32 100644
--- a/Home.md
+++ b/Home.md
@@ -11,6 +11,12 @@
 
 ## Documentation
 
+### Custom Filters
+#### Abbreviations
+Returns an `<abbr>` tag with a definition in the `title` attribute:
+* `{{ "USD" | abbr("United States Dollars") | safe }}` returns `<abbr title="United States Dollars">USD</abbr>`.
+* Use `safe` filter so that HTML is unescaped.
+
 ### Frontmatter
 * `structuredData: none` - Disables "BlogPosting" schema JSON, Open Graph, and Twitter Card metadata, which is by default on for all templates with a `title`.