diff --git a/files/functions_BOOL.csv b/files/functions_BOOL.csv
index 1a56c4e..c7b219c 100644
--- a/files/functions_BOOL.csv
+++ b/files/functions_BOOL.csv
@@ -1,4 +1,4 @@
-operand, arity
+operator, arity
 and,2
 or,2
 not,1
diff --git a/files/functions_CLASSIFY.csv b/files/functions_CLASSIFY.csv
index 2ccf267..33f6af0 100644
--- a/files/functions_CLASSIFY.csv
+++ b/files/functions_CLASSIFY.csv
@@ -1,4 +1,4 @@
-operand, arity
+operator, arity
 +,2
 -,2
 *,2
diff --git a/files/functions_MATCH.csv b/files/functions_MATCH.csv
index 2ccf267..33f6af0 100644
--- a/files/functions_MATCH.csv
+++ b/files/functions_MATCH.csv
@@ -1,4 +1,4 @@
-operand, arity
+operator, arity
 +,2
 -,2
 *,2
diff --git a/files/functions_PLAY.csv b/files/functions_PLAY.csv
index 2ccf267..33f6af0 100644
--- a/files/functions_PLAY.csv
+++ b/files/functions_PLAY.csv
@@ -1,4 +1,4 @@
-operand, arity
+operator, arity
 +,2
 -,2
 *,2