diff --git a/learners/reference.md b/learners/reference.md
index 062f59c7b..c7c37fe4a 100644
--- a/learners/reference.md
+++ b/learners/reference.md
@@ -57,6 +57,10 @@ depending on whether a test is true or false.
 :   (CSV) A common textual representation for tables
 in which the values in each row are separated by commas.
 
+[debug](#debug)
+:   The action of finding and resolving errors (also known as 'bugs') 
+within computer programs or systems.
+
 [default value]{#default-value}
 :   A value to use for a [parameter](#parameter) if nothing is specified explicitly.