diff --git a/Vault-Of-Terminology.md b/Vault-Of-Terminology.md
index d52426c8..6808f16a 100644
--- a/Vault-Of-Terminology.md
+++ b/Vault-Of-Terminology.md
@@ -423,6 +423,11 @@ Vehicle speed sensor
 Variable valve timing  
 </details>
 
+<details markdown="1"><summary><u>WBO</u></summary>
+
+Wide Band Oxygen, same as EGO
+</details>
+
 <details markdown="1"><summary><u>WOT</u></summary>
 
 Wide Open Throttle