diff --git a/sensospot_data/utils.py b/sensospot_data/utils.py
index 046e740..c2ea921 100644
--- a/sensospot_data/utils.py
+++ b/sensospot_data/utils.py
@@ -13,7 +13,7 @@ from .columns import (
     META_DATA_PARAMETERS_CHANNEL,
 )
 
-DEFAULT_AGGREGATION_COLUMNS = [
+DEFAULT_AGGREGATION_INDEX = [
     META_DATA_EXPOSURE_ID,
     META_DATA_WELL_ROW,
     META_DATA_WELL_COLUMN,
@@ -119,7 +119,7 @@ def apply_exposure_map(data_frame, exposure_map=None):
 
 
 def aggregate(
-    data_frame, column, method, on=DEFAULT_AGGREGATION_COLUMNS, new_name=None
+    data_frame, column, method, on=DEFAULT_AGGREGATION_INDEX, new_name=None
 ):
     """returns the aggregates of one data frame column
 
@@ -143,7 +143,7 @@ def aggregate(
 
 
 def add_aggregate(
-    data_frame, column, method, on=DEFAULT_AGGREGATION_COLUMNS, new_name=None
+    data_frame, column, method, on=DEFAULT_AGGREGATION_INDEX, new_name=None
 ):
     """aggregates one column in a data frame and
         adds the resulting column to the data frame