diff --git a/docs/glossary.rst b/docs/glossary.rst
index f19897c..20ad21c 100644
--- a/docs/glossary.rst
+++ b/docs/glossary.rst
@@ -130,6 +130,9 @@
       Memory Tagging Extension. An optional Armv8.5 extension that enables
       hardware-assisted memory tagging.
 
+   LTS
+      Long-Term Support
+
    OEN
       Owning Entity Number