Index: docs/Lexicon.rst
===================================================================
--- docs/Lexicon.rst
+++ docs/Lexicon.rst
@@ -109,6 +109,11 @@
     Garbage Collection. The practice of using reachability analysis instead of
     explicit memory management to reclaim unused memory.
 
+**GVN**
+    Global value numbering. The practice of assigning a value number to
+    variables and expressions. Provably equivalent variables and expressions are
+    assigned the same value number, and may then be transformed or eliminated.
+
 H
 -